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LIBRARY 

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RESEARCHES 


ON    THE" 


CHEMISTRY    OF    FOOD, 


MOTION  OF  THE  JUICES 

IN 

THE    ANIMAL    BODY. 


BY 

JUSTUS  LIEBIG,  M.  D., 

PROFESSOR    OF    CHEMISTRY    IN    THE    UNIVERSITY    OF    GIESSEN. 


EDITED  FROM  THE  MANUSCRIPT  OF  THE  AUTHOR, 

BY  WILLIAM  GREGORY,  M.  D., 

PROFESSOR  OF   CHEMISTRY  IN  THE  UNIVERSITY  OF   EDINBURGH. 


EDITED  FROM  THE  ENGLISH  EDITION, 

BY  EBEN  N.   HORSFORD,  A.  M., 

RUMFORD    PROFESSOR   IN   THE    UNIVERSITY   AT   CAMBRIDGE. 


LOWELL: 
DANIEL    BIXBY    AND    COMPANY. 

1848. 

LIBRARY 

UNIVERSITY  OF  CALIFORNIA 


Entered  according  to  Act  of  Congress,  in  the  year  1848,  by 

DANIEL  BIXBY  AND  COMPANY, 
in  the  Clerk's  Office  of  the  District  Court  of  the  District  of  Massachusetts. 


CAMBRIDGE  I 

M  E  T  C  A  L  F     AND      COMPANY, 

PRINTERS  TO  THE  UNIVERSITY. 


PREFACE. 

TO    THE    AMERICAN    EDITION. 


IN  the  following  pages,  the  style  is  a  little  more 
scientific  than  that  of  the  author's  Agricultural 
Chemistry.  It  may  have  been  made  so,  in  the 
knowledge  that  his  previous  works  have  been  gen- 
erally read,  and  the  readers  thereby  prepared  for 
an  additional  effort  in  the  perusal  of  this. 

A  few  changes  in  terminology  from  the  English 
edition  have  been  made,  not  without  hesitation, 
nor  yet  without  consultation. 

Hydrosulphuric  acid,  for  sulphuretted  hydrogen, 
and  sulphide,  for  sulphuret,  are  already  elsewhere 
in  use. 

The  compounds  formed  by  iodine,  bromine,  and 
chlorine,  when  hydroiodic,  hydrobromic,  and  hy- 
drochloric acids  are  poured  into  salts  of  the  heavier 
metals,  as  silver  and  lead,  are  called  iodides,  bro- 
mides, and  chlorides.  There  is  no  sound  reason 
why  this  nomenclature  should  not  be  extended  to 
the  sulphur  compounds  from  hydrosulphuric  acid 
with  the  same  metals. 


iv  PREFACE    TO    THE    AMERICAN    EDITION. 

The  word  alkaline  is  employed  generally 
among  English  and  American  chemists  with  two 
entirely  distinct  significations,  — 

1st.  As  qualifying  a  reaction,  and  distinguishing 
it  from  acid  or  neutral ;  and, 

2d.  As  indicating  the  base  in  a  salt,  implying 
that  it  is  either  potassa,  soda,  lithia,  or  ammonia. 

The  first  applies  to  solutions,  not  only  of  alka- 
lies, but  of  alkaline  earths  and  many  of  the  high- 
er metallic  oxides,  and  certain  of  the  basic  and 
neutral  salts. 

There  is  here  an  obvious  deficiency.  I  venture 
to  suggest  the  word  alkalic  for  the  second  case, 
where  the  adjective  refers  to  a  salt  of  potassa, 
soda,  lithia,  or  ammonia,  retaining  the  epithet  al- 
kaline exclusively  to  qualify  the  reaction  of  any 
base  or  salt  which  imparts,  in  solution,  a  blue  tint 
to  reddened  litmus,  or  changes  the  yellow  of  cur- 
cuma to  brown. 

This  is  but  adopting  the  nomenclature  of  Ber- 
zelius,  upon  which,  in  fact,  nearly  all  chemists 
act,  in  giving  the  first  place  to  the  base  in  their 
formulae  of  salts. 

The  confusion  which  will  be  avoided  by  the 
employment  of  these  two  words  in  their  respective 
places  will  be  appreciated  by  turning  to  page  82. 
What,  for  example,  is  "an  acid  alkaline  lactate," 
or  a  "  neutral  alkaline  phosphate  "  ? 

On  the  receipt  of  the  first  part,  "  Researches  on 


PREFACE    TO    THE    AMERICAN    EDITION.  V 

the  Chemistry  of  Food,"  there  were  prepared  in 
the  Cambridge  Laboratory,  from  the  flesh  of  wild 
pigeons  (Columba  migratoria],  kreatine,  sarcosine, 
and  inosinic  acid,  in  considerable  quantities.  The 
lean  meat  of  a  hundred  and  forty  pigeons  made  the 
quantities  sufficiently  large  to  operate  upon  advan- 
tageously. The  processes  here  given  are,  with 
the  aid  of  a  good  press,  exceedingly  easy  to  follow. 

The  second  part,  which  was  received  from  the 
author  by  the  steamer  of  the  27th  of  March,  has 
been  translated  and  edited,  as  was  the  first  part,  by 
Professor  Gregory  of  the  University  of  Edinburgh. 

The  importance  of  the  principles  established  in 
relation  to  the  transpiration  of  liquids  must  im- 
press itself  on  every  one  interested  (and  who  is 
not?)  in  the  preservation  of  health. 

In  a  letter  addressed  to  the  editor,  dated  Giessen, 
November  5th,  1847,  Professor  Liebig,  after  briefly 
detailing  the  course  of  experiment  and  general  con- 
clusions, says :  —  "  The  application  of  these  results 
to  the  animal  body  scarcely  requires  more  detailed 
explanation.  The  surface  of  the  body  is  a  mem- 
brane from  which  evaporation  goes  uninterruptedly 
forward.  In  consequence  of  this  evaporation,  all 
the  fluids  of  the  body  acquire,  in  obedience  to  at- 
mospheric pressure,  motion  towards  the  evaporating 
surface.  This  is  obviously  the  chief  cause  of  the 
passage  of  the  nutritious  fluids  from  the  bloodves- 
sels, and  of  their  diffusion  through  the  body. 


vi  PREFACE    TO    THE    AMERICAN    EDITION. 

"  We  know  now  what  important  functions  the 
skin  (and  lungs)  fulfil  through  evaporation.  It  is 
a  condition  of  nourishment,  and  the  influence  of  a 
moist  or  dry  air  upon  the  health  of  the  body,  or  of 
mechanical  agitation  by  walking  or  running,  which 
increases  the  perspiration,  is  self-evident." 

In  view  of  the  results  of  this  investigation,  the 
author  remarks,  in  a  letter  bearing  date  January 
6th,  1848:  —  "I  consider  this  investigation  the 
most  important  I  have  ever  made." 

This  estimate  which  Professor  Liebig  has  placed 
upon  his  own  work  will  make  it  not  the  less  ac- 
ceptable to  the  physiological  public.  It  will  be 
read  with  increased  interest  from  the  attention 
which  Matteucci's  work,  and  particularly  that  part 
of  it  relating  to  Endosmosis  and  Exosmosis,  has 
called  to  this  department  of  inquiry. 

The  susceptibility  of  some  persons  to  changes  in 
the  condition  of  the  atmosphere,  the  value  of 
Franklin's  air-bath,  the  advantages  of  regular  sea 
or  fresh-water  bathing,  some  of  the  effects  of  hy- 
dropathic treatment,  the  consequences  of  drought 
on  vegetation,  the  renewed  greenness  and  life  after 
a  shower,  the  influence  of  winds  blowing  from  off 
a  sheet  of  water,  a  mountain,  or  a  sand-plain,  and 
many  other  phenomena  hitherto  but  obscurely 
understood,  all  find  a  more  or  less  perfect  expla- 
nation in  the  experimental  results  recorded  in  the 
following  pages. 


PREFACE   TO    THE    AMERICAN    EDITION.  Vll 

In  relation  to  the  potato  disease,  the  views  of 
the  author  give  harmony  to  a  large  class  of  facts 
upon  record,  and  the  method  of  Dr.  Klotzsch, 
which  promises  so  well,  seems  a  practical  applica- 
tion of  these  views. 

It  has  been  stated,  that,  during  the  last  year  or  the 
year  previous,  several  swaths  were  spread  through 
a  potato  field  while  the  tops  were  young  and 
green,  and  that  those  hills,  the  tops  of  which  had 
been  partly  removed,  contained  at  harvest  time  only 
sound  potatoes,  while  everywhere  else  throughout 
the  field  the  tubers  were  infected  by  the  rot. 

A  farmer  on  Long  Island  caused  the  blossoms  as 
they  appeared  in  his  potato  field  to  be  picked  off, 
and  found  only  sound  potatoes  in  the  hills  at  har- 
vest time. 

These  facts  have  a  new  interest  and  significance 
from  the  support  which  they  lend  to  the  views  of 
Baron  Liebig  and  the  method  of  Dr.  Klotzsch. 

It  is  to   be   hoped  that  this  method  will  meet 

with  a  faithful  trial. 

EBEN   N.   HORSFORD. 

CAMBRIDGE,  May  12,  1848. 


CONTENTS. 


ON  THE  CHEMISTRY  OF  FOOD. 

PAGE 

PREFACE  TO  THE  ENGLISH  EDITION xxi 

AUTHOR'S  PREFACE    .  .         *  xxix 


SECTION   I. 

On  the  methods  of  investigation  to  be  pursued  in  Animal 

Chemistry 1 

Want  of  connection  between  Chemistry  and  Physiology    .  4 

Animal  tissues  and  compounds  act  as  ferments       ...  6 

The  changes  going  on  in  the  body  are  little  known    .        .  8 
The  results  of  ultimate  analysis  of  animal  substances  have 

been  unsatisfactory 9 

Necessity  for  control  to  ultimate  analysis    ....  10 

Erroneous  methods  of  control  adopted 11 

Mulder's  theory  of  Proteine 13 

It  is  not  tenable 13 

Theories  are  never  absolutely  true,  but  only  true  for  the  period  15 
Fallacious  conclusions  drawn  from  the  analysis  of  fibrine,  al- 
bumen, &c 16 

Identity  of  composition  not  necessary 17 

Erroneous  views  deduced  from  the  Proteine  theory    .         .  17 

Proteine  does  not  exist 21 

There  is  much  to  be  done  in   regard  to  the  constitution  of 

fibrine,  albumen,  &c 22 


X  CONTENTS. 

SECTION   II. 

Acid  reaction  of  the  juice  of  flesh            .....  23 

Observations  of  Berzelius  on  the  juice  of  flesh  ...  23 

The  presence  of  lactic  acid  in  it  doubtful        ....  24 

Kreatine  discovered  by  Chevreul,  in  1835  ....  27 

His  account  of  it     .         . 27 

Berzelius  on  kreatine 28 

Wohler  and  Schlossberger  on  kreatine 29 

Investigation  of  the  juice  of  flesh 30 

Extraction  of  the  soluble  constituents  of  flesh         ...  31 

It  is  necessary  to  use  large  quantities           ....  32 

Game  and  fowl  yield  most  kreatine 34 

The  liquid  always  acid,  even  when  mixed  with  blood         .  34 

Separation  of  the  phosphoric  acid 35 

Modification  of  the  process  for  fish 36 

Kreatine  crystallizes 36 

Its  amount  in  different  kinds  of  flesh           ....  37 

It  occurs  in  all  the  higher  animals 38 

Kreatine 39 

Analysis  of  kreatine 39 

Properties  of  kreatine 42 

Action  of  acids  and  bases  on  it 43 

Kreatinine,  its  preparation 44 

Its  properties 46 

It  is  a  powerful  base 47 

Its  composition 48 

Its  relation  to  kreatine 48 

Analysis  of  kreatinine 49 

Kreatine  and  kreatinine  in  urine         .....  50 

Pettenkofer's  compound 50 

Improved  method  of  preparing  it         .         .         .                  .  51 

It  consists  of  kreatinine  and  kreatine      .....  53 

Kreatinine  alone  is  found  in  putrid  urine    ....  53 

Salts  of  kreatinine 55 

Sarcosine,  its  preparation    .....  56 

Its  properties  ........  53 


CONTENTS.  XI 

Its  analysis 58 

Salts  of  sarcosine '59 

Its  formula 61 

Its  relation  to  kreatine 62 

It  is  isomeric  with  lactamide  and  with  urethane  .  .  63 

Inosinic  acid,  its  preparation 63 

Its  analysis 65 

Its  formula 66 

Inosinates 66 

Probable  constitution  of  the  acid 69 

Kreatinine  exists  ready  formed  in  flesh  ....  70 

Lactic  acid,  as  a  constituent  of  flesh 73 

Method  of  extracting  it 73 

Modification  of  the  process  for  fish  .....  74 

Analysis  of  lactates  from  flesh  and  fish  ....  75 
Inorganic  constituents  of  the  juice  of  flesh  .  .  .77 

Large  amount  of  inorganic  salts  in  flesh  ....  77 

Large  proportion  of  soluble  phosphates 77 

The  ashes  of  flesh  contain  no  carbonates,  only  phosphates 

and  chlorides 78 

The  different  modifications  of  phosphates  are  present  in  these 

ashes 79 

Characters  of  the  phosphates 79 

In  certain  kinds  of  flesh,  the  whole  alkalies  are  not  sufficient 

to  form  tribasic  phosphates 82 

In  fowl  they  are  not  sufficient  even  to  form  bibasic  phosphates  82 
Equilibrium  between  the  free  lactic  and  phosphoric  acids  in 

the  juice  of  flesh 83 

The  ashes  of  flesh  always  alkaline 83 

Importance  of  these  facts  in  explaining  the  vital  processes  84 
Lactic  acid  cannot  be  detected  in  normal  urine,  whether  it 

be  acid  or  alkaline 84 

It  is  therefore  consumed  in  the  respiratory  process,  and  in  this 

form  sugar,  starch,  &c.,  are  employed  in  respiration  .  86 
The  blood  and  lymph  are  always  alkaline,  the  juice  of  mus- 
cle is  always  acid 86 

These  conditions  may  give  rise  to  electrical  currents  .  87 


Xii  CONTENTS. 

The  juice  of  flesh  contains  phosphate  of  potash  and  chloride 

of  potassium 87 

While  blood  and  lymph  contain  phosphate  of  soda  and  chlo- 
ride of  sodium 87 

Relative  proportions  of  soda  and  potash  in  the  juice  of  flesh 

and  in  blood .87 

The  juice  of  flesh,  if  it  could  be  obtained  free  from  blood  and 

lymph,  would  perhaps  contain  no  soda   ....  89 

The  permeability  of  the  vessels  for  the  different  fluids  must 

be  different 89 

Morbid  accumulation  of  free  acid  destroys  the  bones          .  90 
Importance  of  chloride  of  sodium  as  a  part  of  the  food  of  ani- 
mals      ,90 

Inland  plants  contain  only  salts  of  potash  ....  91 

Maritime  and  even  sea  plants  contain  much  more  potash  than 

soda .91 

Mutual  action  of  phosphate  of  potash  and  chloride  of  sodium        92 

It  produces  phosphate  of  soda 93 

Phosphate  of  soda  is  indispensable  to  the  blood      ...      93 
Its  importance  in  respiration       ......  93 

Relation  of  blood  to  carbonic  acid  gas     .....       93 

Its  absorbent  power  is  not  owing  to  the  presence  of  carbonate 

of  soda 94 

Experiments  to  prove  this       .......       95 

Remarkable  properties  of  phosphate  of  soda,  to   which  the 
blood  owes  its  power  of  absorbing  and  giving  off  carbonic 

acid 97 

The  study  of  the  influence  of  salts,  acids,  and  alkalies  on 
respiration  and  digestion  will  lead  to  valuable  results  in 

medicine 100 

Relative  proportions  of  lime  and  magnesia  in  the  juice  of  flesh     100 

SECTION  III. 

General  results 101 

Practical  applications  to  cookery 101 

Action  of  cold  water  on  flesh      ...  102 


CONTENTS.  xiii 

Stock  contains  the  soluble  constituents  of  flesh  .  .  .  103 

Nature  of  soup 103 

Albumen  in  flesh  .........  104 

It  is  the  cause  of  tenderness 104 

Action  of  hot  water  on  flesh 105 

Best  method  of  boiling  meat 105 

Temperature  required 105 

Underdone  meat 105 

Poultry  sooner  done  than  beef  or  mutton  ....  106 

Use  of  a  covering  of  lard  in  roasting 106 

Best  method  of  boiling  meat  to  obtain  soup  from  it  .  .  106 
The  bouilli  is  neither  nutritious  nor  digestible  without  the 

soup 107 

Gelatine  not  the  source  of  the  strength  or  flavor  of  soup  .  107 

Amount  of  gelatine  dissolved  by  boiling  water  .  .  .  107 

Amount  of  matter  dissolved  by  cold  water  ....  108 

Poultry  contains  much  soluble  matter  .  .  .  .  109 
The  nutritious  and  sapid  ingredients  of  soup  exist  in  it  ready 

formed 109 

Best  mode  of  preparing  soup 109 

Influence  of  the  color  of  soup  on  our  judgment  of  its  taste  .  109 

Extract  of  meat,  or  true  portable  soup  ....  110 

The  portable  soup  of  commerce  is  nearly  pure  gelatine  .  110 

Beef  yields  ^d  of  extract 1 10 

Extract  of  meat  recommended  as  a  restorative  for  wounded 

persons 110 

Characters  of  true  and  false  extract  .  .  .  .  Ill 
Extract  of  meat  will  be  useful  in  ships,  fortresses,  &c.,  where 

much  salt  meat  is  consumed Ill 

Salting  of  meat  . Ill 

The  brine  contains  the  soluble  ingredients  ....  Ill 

Salt  meat  is  therefore  deficient  in  nutritive  qualities  .  .  112 

Causes  of  this 112 

Effects  produced  by  salt  containing  chlorides  of  calcium  and 

magnesium 113 

Meat  salted  with  such  salt  may  be  less  unwholesome  .  .113 

Flesh  compared  with  other  animal  food  .  .  .  .  114 


CONTENTS. 

The  soluble  constituents  of  muscles  must  be  essential  to  their 

functions H4 

Lactic  acid  exists  in  the  gastric  juice 

The  digestive  process,  in   a  chemical  point  of  view,  now 

cleared  up •     115 

The  gastric  juice  resembles  the  juice  of  flesh     .         .         .         115 
Soup  or  extract  of  flesh  suggested  as  a  remedy  for  dyspepsia, 

and  for  convalescents 115 

Origin  of  hydrochloric  and  other  volatile  acids  in  the  gastric 

juice 

CONCLUSION. 

These  researches  are  only  the  commencement  of  what  must 

be  an  extensive  series  .         « 116 

Various  substances  distinguishable  in  the  muscular  substance      116 

True  province  of  chemical  analysis 117 

Kreatine  and  kreatinine,  occurring  both  in  muscle  and  in 
urine,  must  serve  some  purpose  in  the  organism  not  yet 

ascertained 117 

There  is  a  gelatinous  substance,  not  gelatine,  in  the  cold  infu- 
sion of  flesh,  not  yet  studied 117 

Also,  a  body  resembling  caseine,  not  yet  examined         .         .     117 
Also,  two  new  nitrogenized  acids,  not  yet  investigated       .         118 
The  juice  of  flesh  appears  to  contain  neither  urea  nor  uric  acid     118 
But  on  one  occasion  the  author  obtained  a  trace  of  a  substance 
resembling  uric  acid     .         .         .         .         .         .         .         .118 


CONTENTS.  XV 


ON  THE   MOTION   OF  THE   JUICES   IN  THE 
ANIMAL   BODY. 

PAGE 

PREFACE  TO  THE  ENGLISH  EDITION          ....         123 
AUTHOR'S  PREFACE       ....  .     127 


On  the  phenomena  accompanying  the  mixture  of  two  liquids 

separated  by  a  membrane 129 

Relation  of  porous  bodies  to  water  and  other  liquids       .         .  130 
The  moistening  of  porous  bodies  depends  on  capillary  attrac- 
tion         .                         131 

Pressure  required  to  cause  liquids  to  pass  through  membranes  133 
The  pressure  varies  with  different  liquids       ....  134 
The  absorbent  power  of  the  membrane  has  a  share  in  the  ef- 
fect             135 

Action  of  brine,  oil,  alcohol,  &c.,  on  moist  membranes           .  136 
Cause  of  the  shrivelling  of  membranes  when  strewed  with 

salt 138 

Animal  tissues  are  permeable  to  all  liquids     ....  140 
Saline  solutions,  alcohol,  &c.,  mix  with  water  through  mem- 
branes        141 

Change  of  volume  when  two  dissimilar  liquids  mix  through 

a  membrane  ;  Endosmosis 142 

This  change  of  volume  does  not  depend  alone  on  the  differ- 
ent densities 143 

Phenomena  of  the  mixture  of  two  liquids  through  a  membrane  143 

The  mixture  is  the  result  of  chemical  attraction      .        .         .  149 

Chemical  attraction  is  everywhere  active   ....  150 

Examples. —  Crystallization 151 

Action  of  solids  on  dissolved  matters           ....  153 
Laws  of  the  mixture  of  two  dissimilar  liquids         .         .         .  155 
Effect  of  the  interposition  of  a  membrane           .         .         .  159 
The  change  of  volume  in  two  liquids  which  mix  through  a 
membrane  is  the  result  of  chemical  affinity  modifying  ca- 
pillary attraction 160 


XVI  CONTENTS. 

Effect  of  evaporation  on  liquids  confined  by  membranes  .  162 

Views  of  Magnus  on  Endosmosis 163 

Remarks  on  his  theory 164 

The  nature  of  the  membrane  has  an  important  influence  .  166 
Unequal  attraction  of  membranes  for  different  liquids  .  167 
The  action  of  two  liquids,  separated  by  a  membrane,  is  equiv- 
alent to  pressure,  unequal  on  opposite  sides  .  .  .  169 
Causes  which  influence  the  mixture  of  two  liquids  separated 

by  a  membrane 174 

These  causes  produce,  in  the  animal  body,  absorption  of  the 

fluids  of  the  intestines  into  the  blood  .  .  .  .175 

Effects  of  drinking  water  and  saline  solutions  of  different 

strengths 176 

Influence  of  the  cutaneous  evaporation  on  the  motion  of  the 

animal  juices 179 

Experiments 180 

Influence  of  the  atmospheric  pressure 182 

Water  passes  through  membranes  more  easily  than  air  does  184 

Experiments  on  evaporation  through  membranes    .         .         .  185 

Importance  of  the  cutaneous  transpiration          .         .         .  187 

By  it  the  fluids  acquire  a  motion  towards  the  skin  and  lungs  188 

Effects  of  dry  and  moist  air,  and  of  elevation,  on  the  health  188 

Causes  of  the  efflux  of  sweat           ......  190 

Fishes  die  in  air,  because  the  due  distribution  of  the  fluids  is 

prevented 190 

Experiments  of  Hales  on  the  motion  of  the  sap  in  plants  .  190 

This  motion  is  caused  by  evaporation  ....  192 

Force  with  which  the  sap  rises 192 

The  atmospheric  pressure  is  the  active  force  .  .  .  193 

The  sap  absorbs  gases 194 

The  evaporation  supplies  food  to  the  plant  .  .  .  195 

Influence  of  suppressed  evaporation  on  hop-vines  .  .  195 

Observations  of  Hales  on  the  blight  in  hops,  &c.  .  .  195 

Fire-blasts  in  hops 197 

Hales  recognized  the  influence  of  evaporation  on  the  life  of 

plants 197 

The  origin  of  the  potato  disease  is  probably  similar  to  that  of 

the  blight  in  hops 198 


CONTENTS.  XV11 

The  disease  long  known      .......  198 

It  is  due,  not  to  a  degeneration  of  the  plant,  but  to  a  combi- 
nation of  external  circumstances          .....  199 

It  is  connected  with  the  weather,  and  particularly  with  the 

temperature  and  hygrometric  state  of  the  atmosphere     ,  200 

The  life  of  plants  is  dependent  chiefly  on  four  external  causes  201 
Only  one  of  which,  namely,  the  quality  of  the  soil,  is  in  the 

power  of  the  agriculturist 201 

Effects  of  suppressed  evaporation                         ;  202 
The  fungi  and  putrefaction  follow  the  death  of  the  plant        .  202 
Observations  of  Hales  on  the  rise  of  the  spring  sap  in  per- 
ennial plants 202 

Views  of  Dutrochet 202 

Objections  to  these  views 203 

The  cause  of  the  rise  of  the  sap  is  transient,  and  depends  on 

external  influences       .         .         .         .         .         .         .         .  204 

It  exists,  not  merely  in  the  spongioles,  but  in  all  parts  of  the 

plant 205 

Experiments  of  Hales     .........  205 

His  conclusions .        .  206 

Gas  is  given  off  by  the  sap 208 

The  rise  may  therefore  be  due  to  disengagement  of  gas       .  208 

The  gas  is  probably  carbonic  acid 209 


APPENDIX. 

Results  of  Guckelberger's  investigation,  sustaining  the  view, 
that  organized  bodies,  such  as  fibrine,  albumen,  and  caseine, 
are  groups  of  already  formed' organic  compounds  .  .  211 

Account  of  a  plan  proposed  by  Dr.  Klotzsch,  of  Berlin,  for 
protecting  potato  plants  from  disease  ....     213 

This  plan  published  by  authority  of  the  Minister  of  the  Inte- 
rior of  Prussia,  on  the  favorable  report  of  the  President  of 
the  College  of  Rural  Economy  at  Berlin  ....  218 

Conditions  on  which  the  reward  claimed  for  his  plan,  if 
found  effectual,  by  Dr.  Klotzsch,  has  been  granted  .  .  218 


I 


RESEARCHES 


CHEMISTRY  OF  FOOD. 


PREFACE 

TO    THE    ENGLISH    EDITION. 


IN  offering  to  the  British  public  the  present 
translation  of  the  latest  work  of  Baron  Liebig,  I 
may  be  permitted  to  say,  that  I  feel  highly  hon- 
ored in  being  intrusted  with  the  duty  of  convey- 
ing to  my  countrymen  a  knowledge  of  one  of  the 
most  interesting  and  valuable  investigations  which 
has  yet  been  made  in  Animal  Chemistry. 

The  researches  into  the  nature  of  the  soluble 
constituents  of  muscle  or  flesh,  which  constitute 
the  chief  part  of  the  present  work,  are  preceded 
by  considerations  on  the  true  Method  of  Research 
in  Animal  Chemistry,  which  are  worthy  of  the 
most  earnest  attention  on  the  part  of  those  who 
intend  to  devote  themselves  to  investigations  in 
this  most  important  and  at  the  same  time  most 
difficult  department  of  science.  A  careful  study 
of  this  section  will  convince  the  reader  that  much 
more  might  have  been  done  of  late  years  in  Phys- 
iological Chemistry,  but  for  the  wrong  direction 


XXU  PREFACE    TO    THE    ENGLISH    EDITION. 

unfortunately  given  to  recent  researches,  and  will 
powerfully  contribute  to  direct  into  the  right  chan- 
nel the  energies  of  those  rising  chemists  to  whom 
Britain  must  look  to  sustain  her  scientific  reputa- 
tion in  the  present  age  df  rapidly  advancing  dis- 
covery in  the  most  recondite  parts  of  Organic 
Chemistry  and  of  Physiology. 

The  physiologist  will  also  find,  in  this  introduc- 
tory section,  the  most  convincing  reasons  to  show 
that,  henceforth,  it  is'  indispensable  that  Anatomy, 
structural  Physiology,  and  Chemistry  should  unite 
their  forces  with  a  view  to  the  solution  of  the 
great  questions  which  it  is  the  common  object  of 
these  sciences  to  solve. 

With  regard  to  the  chemical  researches  con- 
tained in  the  present  work,  it  is  most  emphatical- 
ly to  be  stated,  that  they  constitute  only  the  first 
steps  in  an  almost  new  career  ;  that  they  are  very 
far  from  exhausting  even  the  single  subject  here 
investigated,  namely,  the  nature  of  the  soluble 
constituents  of  the  muscles ;  and  that,  consequent- 
ly, they  are  chiefly  valuable  as  indicating  the  true 
path  at  present  to  be  pursued  by  chemists.  It 
would  be  contrary  to  the  principles  as  well  as  to 
the  wishes  of  their  author,  if  physiologists  were 
to  regard  them  as  completed,  or  as  in  any  one 
point  exhausting  the  subject ;  and  how  many  more 
subjects  does  the  animal  organism  present,  which 
must  remain  obscure  and  impenetrable  till  they 


PREFACE    TO    THE    ENGLISH    EDITION.  XX111 

shall  be  studied  on  principles  analogous  to  those 
which  have  guided  the  author? 

Nevertheless,  these  researches  have  already 
thrown  much  light  on  many  important  but  ob- 
scure questions  ;  and  independently  of  the  interest 
which,  in  a  purely  chemical  view,  they  must  al- 
ways have  for  the  chemist,  they  will  be  found, 
by  the  physiologist  and  the  medical  man,  both 
interesting  and  valuable  in  a  very  high  degree. 

In  connection  with  previous  researches,  they 
serve  to  demonstrate,  that,  the  more  we  know  of 
the  processes  going  on  in  the  organism,  the  more 
do  we  find  these  to  involve  strictly  chemical 
changes,  and  to  be  capable  of  a  chemical  inter- 
pretation. •  It  would  indeed  appear  as  if  every 
change  in  the  organism  were  attended  by  a  defi- 
nite chemical  or  physical  action ;  and  although  we 
shall  probably  never  succeed  in  unveiling  the  na- 
ture of  the  peculiar  influence,  called  vitality,  under 
which  these  changes  occur,  yet  the  present  as  well 
as  previous  investigations  render  it  certain  that  we 
have  still  a  great  deal  more  to  discover  concerning 
the  share  taken  by  chemical  action  in  the  vital 
processes. 

I  cannot  omit  to  direct  the  attention  of  physiol- 
ogists to  the  proofs,  contained  in  the  following 
pages,  of  the  truth  of  the  principle,  that  every 
property,  however  apparently  trifling  or  minute, 
possessed  by  any  constituent  of  the  organism,  even 


XXIV  PREFACE    TO    THE    ENGLISH    EDITION. 

by  such  as  occur  only  in  very  small  proportion, 
has  its  destined  use  and  function ;  and,  conse- 
quently, that  every  constant  difference,  whether  of 
composition,  of  form,  or  of  quality,  in  the  different 
tissues  and  fluids,  must  likewise  correspond  to  a 
difference  of  function,  in  which,  as  a  general  rule, 
it  cannot  be  replaced,  nor  its  absence  compensated 
for,  by  any  other  substance,  however  analogous  in 
most  of  its  properties. 

A  striking  example  of  this  truth  will  be  found 
in  the  facts  concerning  the  great  preponderance  of 
phosphate  of  potash  and  chloride  of  potassium  in 
the  juice  of  flesh,  while  in  the  blood  and  lymph 
which  circulate  through  the  muscles,  it  is  phos- 
phate of  soda  and  chloride  of  sodium  which  pre- 
vail. Another  will  be  found  in  the  fact,  that  the 
juice  of  flesh  is  always  strongly  acid,  while  the 
blood  and  lymph  are  decidedly  alkaline ;  and  a 
third  is  seen  in  the  abundant  supply  of  lactic  acid 
in  the  juice  of  flesh,  while  it  cannot  be  detected 
in  the  urine. 

But  perhaps  the  most  interesting  observation, 
next  to  the  discovery  of  kreatine  as  a  constant  in- 
gredient of  flesh,  of  kreatinine,  a  powerful  base, 
in  the  juice  of  flesh,  and  of  both  in  urine,  is  the 
demonstration,  complete,  as  it  appears  to  me,  of 
the  true  function  of  the  phosphate  of  soda  in  the 
blood.  This  function,  that  of  absorbing  carbonic 
acid  and  giving  it  out  in  the  lungs,  is  here  shown 


PREFACE    TO    THE    ENGLISH   EDITION.  XXV 

to  depend  entirely  on  the  minute  chemical  charac- 
ters of  the  salt  in  question  ;  and  we  now  see  how 
it  happens  that  phosphate  of  soda  is  essential  to 
the  blood,  and  cannot  be  replaced  by  phosphate 
of  potash,  a  salt  which,  although  in  many  points 
analogous,  differs  entirely  from  phosphate  of  soda, 
in  its  tendency  to  acquire  an  acid  instead  of  an  al- 
kaline reaction,  and  in  its  relation  to  carbonic  acid. 
In  this  way,  the  beautiful  researches  of  Graham  on 
the  phosphates  are  now  finding  their  application, 
in  the  minutest  point,  to  Physiology.  The  same 
remark  applies  to  the  action  of  common  salt  on 
phosphate  of  potash,  which  satisfactorily  accounts 
for  the  presence  of  phosphate  of  soda  in  the  blood 
of  animals  whose  food  contains  only  phosphate  of 
potash,  but  which  either  find  common  salt  in  their 
food,  or  obtain  it  as  an  addition.  Surely,  such 
facts  as  these  must  convince  all  men  of  the  value 
of  the  most  minute  study  of  the  chemical  prop- 
erties of  all  the  substances  which  occur  in  the 
organism,  however  these  properties  may  at  first 
appear  trifling  or  unimportant ;  and  of  the  utter 
impossibility  of  making  progress  in  Physiology 
without  the  aid  of  Chemistry.  I  would  also  direct 
attention  to  the  evidence  here  given  of  the  fact, 
that  the  parietes  of  the  different  systems  of  ves- 
sels, as  well  as  the  membranes  and  cells,  must 
possess,  in  the  living  body,  a  power  of  selection, 


XXvi  PREFACE    TO    THE    ENGLISH    EDITION. 

or,  in  other  words,  different  degrees  of  permeabili- 
ty, in  reference  to  the  various  substances  which 
penetrate  them  by  endosmose. x  To  this  subject 
the  investigations  of  the  author  have  been  more 
particularly  directed,  since  the  termination  of  the 
present  work  ;  and  results  of  great  interest  and 
value  have  been  already  obtained. 

The  medical  man  will  find  in  these  Researches 
a  prospect  of  many  and  great  improvements  in 
practice,  whether  as  regards  dietetics,  or  the  action 
of  acids,  alkalies,  and  salts  on  the  digestive  and 
respiratory  processes  ;  and  with  respect  to  both, 
it  is  to  Chemistry  that  he  must  look  for  assistance 
in  his  efforts  to  advance.  Lastly,  the  present  work 
contains  some  most  valuable  practical  applications 
of  the  chemical  discoveries  therein  detailed  to  an 
art  which  immediately  concerns  the  whole  of  man- 
kind ;  namely,  the  culinary  art. 

The  subjects  of  the  preparation  of  meat  for  food 
by  boiling,  roasting,  and  stewing  ;  the  true  nature 
and  proper  mode  of  preparation  of  soup,  as  well 
as  of  the  extract  of  flesh  or  genuine  portable  soup  ; 
and,  finally,  the  changes  produced  in  meat,  not 
only  by  the  above  processes,  but  by  salting,  and 
the  conditions  necessary  in  each  case  to  insure  the 
digestibility  and  nutritive  qualities  of  the  flesh  or 
soup,  are  here,  for  the  first  time,  investigated  on 
scientific  principles ;  and  in  all  these  points,  Chem- 


PREFACE    TO    THE    ENGLISH    EDITION.  XXV11 

istry  is  found  to  be  the  means  of  throwing  light 
on  that  which  was  obscure,  and  of  improving  our 
practice  by  the  application  of  rational  principles. 

In  conclusion  I  would  remark,  that  the  apparent 
simplicity  of  the  results,  and  even  of  the  processes 
described,  gives  a  very  inadequate  idea  of  the  la- 
borious and  difficult  nature  of  the  investigation. 
Having  myself  repeated  several  of  these  processes, 
I  have  been  enabled  to  perceive,  that,  unless  Baron 
Liebig  had  devoted  to  the  subject  his  whole  ener- 
gies for  a  long  time,  and  unless,  moreover,  he  had 
operated  on  a  scale  so  large  as  few  experimenters 
would  have  ventured  on,  the  whole  subject  would 
have  remained  as  obscure  as  ever.  Not  the  least 
valuable  lesson  to  be  derived  from  this  work  is 
the  absolute  necessity  of  experimenting  on  a  very 
large  scale,  if  we  would  obtain  satisfactory  or 
trustworthy  results. 

WILLIAM   GREGORY. 

UNIVERSITY  OF  EDINBURGH, 
31st  May,  1847. 


AUTHOR'S  PREFACE. 


THE  preparation  of  a  new  edition  of  my  Animal 
Chemistry  rendered  it  desirable,  and  even  neces- 
sary, to  subject  to  an  experimental  inquiry  and 
criticism  the  chemical  observations  made,  up  to 
that  period,  in  this  department  of  the  science.  I 
was  thus  induced  to  engage  in  a  series  of  research- 
es, which  have  led  me  farther  than  I  at  first  anti- 
cipated. The  questions  as  to  the  nature  of  the 
organic  acid  diffused  through  the  muscular  system, 
and  that  of  the  other  substances  contained  in  that 
system,  appeared  to  me  so  important  for  the  right 
understanding  and  explanation  of  the  vital  pro- 
cesses, that  I  did  not  feel  justified  in  proceeding 
with  the  revisal  of  my  work  until  these  questions 
had  been,  at  least  to  a  certain  extent,  experimen- 
tally answered. 

The  present  little  work  contains  the  analyti- 
cal details  of  my  investigation  on  these  subjects, 
which,  in  accordance  with  the  plan  of  the  Animal 


xxx  AUTHOR'S  PREFACE. 

Chemistry,  could  not  be  introduced  into  that  work. 
As  my  experiments  include  the  changes  which 
flesh  undergoes  in  its  preparation  for  food,  I  trust 
that  not  only  physiologists  and  chemists,  but  also 
the  lovers  of  a  rational  system  of  diet,  will  find  in 
the  following  pages  many  observations  worthy  of 

their  attention. 

DR.  JUSTUS  LIEBIG. 

GIESSEN,  1st  June,  1847. 


RESEARCHES 


CHEMISTRY   OF   FOOD. 


SECTION  I.  —  INTRODUCTORY. 

On  the  Methods  of  Investigation  in  Animal  Chemistry. 

IF  we  consider  with  some  attention  the  facts  which  chemists 
have  been  ascertained  in  Animal  Chemistry,  we  shall  voted  their  ° 
be  surprised  to  find  how  few  among  them  there  are  on  AnTmaf 
which  conclusions  can  be  securely  based.     The  cause  and'p'hysi- 
of  this  appears  to  me  to  be,  that  hitherto  but  a  very 
small  number,  comparatively,  of  professional  chemists 
have  occupied  themselves  with  the  cultivation  of  this 
department  of  the  science,  or  have  selected  it  as  the 
object  of  profound  and   thorough  investigation.     The 
important  researches  which  Berzelius  began  forty  years 
ago,  as  well  as  those  of  L.  Gmelin,  Braconnot,  and 
Chevreul,  have  not  been  imitated  or  followed  up  in  the 
same  spirit  which  animated  these  men.     No  chemist 
has  yet  appeared  who  has  chosen,  in  Animal  Physiol- 
ogy, as  De  Saussure  did  in  Vegetable  Physiology,  the 
first  and  most  important  questions  as  the  problem  of  his 
life.    Hence  it  comes,  that  in  Animal  Chemistry,  which 
1 


2  METHODS    OF    INVESTIGATION 

Animal  is  a  frontier  district,  belonging  entirely  neither  to  Chem- 
bMtoa  in  istry  nor  to  Physiology,  as  commonly  happens  on  the 
adventurers0  frontiers  of  thinly-peopled  countries,  adventurers  of  all 
kinds  roam  about ;  and  it  is  on  the  observations  made, 
and  the  tales  related  by  these  adventurers,  during  their 
occasional  expeditions  or  excursions,  that  the  greater 
part  of  our  knowledge  of  this  district  rests.  But  how 
few  of  them  have  attained  so  accurate  a  knowledge, 
even  of  the  small  tract  over  which  they  have  passed, 
that  those  who  follow  them  run  no  risk  of  losing  their 
way  !  It  is  one  thing  to  travel  through  a  country,  and 
another,  very  different,  to  establish  a  home  therein. 
Conaequen-  Since  none  of  those  philosophers  who  are  called  to 
possess  this  country,  and  who  should  draw  from  its 
fertile  soil  useful  fruits,  in  the  form  of  prolific  points  of 
view,  and  imperishable  truths,  takes  the  trouble  to  fol- 
low the  devious  path  of  these  adventurers,  and  to  test 
the  accuracy  of  their  statements,  they  are  induced 
either  to  reject  all  these  tales  as  vague  and  unfounded, 
or  to  regard  them  as  actual  truths.  If  one  experiment- 
er, for  example,  has  found,  in  this  or  in  that  quarter, 
nothing  which  seemed  worthy  of  his  attention,  they 
conclude  that  there  is  nothing  whatever  to  be  found 
there  ;  and  if  another  proclaims  the  rich  treasures  of  a 
different  district,  they  act  as  if  they  were  already  in 
possession  of  these  ;  they  build  bridges  over  rivers, 
and  drive  mills  with  their  waterfalls  ;  but  these  are 
bridges  over  which  no  one  passes,  and  mills  that  yield 
us  no  flour. 

Exploded  er-  For  centuries  past,  men  have  endeavoured  to  dis- 
icai  theory,  cover  methods  of  cure,  or  a  knowledge  of  morbid  con- 
ditions, by  the  aid  of  the  imagination  in  the  so-called 
systems  of  medicine  ;  as  if  it  were  possible,  oi^even 
wise  and  judicious,  to  expect  a  true  insight  into  these 
things,  or  to  look  for  intellectual  illumination  and  prog- 
ress from  the  most  hazardous  of  all  games  of  chance. 


IN    ANIMAL    CHEMISTRY.  3 

In  modern  times  this  method  has  been  abandoned  as  The  chemist 

has  no  direct 

entirely   unproductive  ;    but,  on  the  other  hand,  men  interest  in 

-,      /,  Physiology 

commit  an  error  not  less  grave,  inasmuch  as,  instead  01  and  Pathoi- 
acquiring  by  their  own  researches  the  knowledge  ne-  °gy' 
cessary  for  the  solution  of  their  difficulties,  they  leave 
this  duty  to  others,  who,  fully  occupied  with  the  culti- 
vation of  their  own  branch  of  science,  have  neither 
interest  in  the  questions  to  be  solved,  nor  inclination 
for  the  task.  From  the  chemical  analysis  of  blood,  of 
urine,  or  of  a  morbid  product,  they  expect  an  aid 
which  these  analyses  can  never  afford,  as  long  as  the 
results  of  the  chemist  are  not  brought  into  the  true  con- 
nection with  the  conditions  which  they  are  to  explain, 
or  with  the  causes  which  have  produced  these  condi- 
tions. All  the  new  facts  daily  ascertained  by  the  Pathoiogists 

i  111  11-  i     •  i      neglect    pure 

chemist  are  regarded  by  pathologists  as  being  exactly  chemistry, 
those  which  are  of  no  direct  use  to  them,  because  they 
have  no  clear  idea  of  that  which  they  require  ;  be- 
cause they  are  unable  to  connect  with  these  chemical 
discoveries  any  question  to  be  solved,  or  to  draw  from 
them  any  conclusion. 

What  an  inconceivable  delusion,  what  a  confusion  of  Erroneous 
ideas  must  exist,  when  a  physician  thinks,  that,  from  gard  to  the 
the  complex  results  of  an  analysis  of  the  blood,  he  can  connection 
draw  a  conclusion  as  to  the  nature  and  the  cause  of  a  icTnTamf1" 
disease,  and  can  found  on  this  a  method  of  treatment,  chemlstry- 
when  we  have  not  yet  advanced  so  far  in  physiology  as 
to  bring  into  relation  with  the  digestive  process  one  of 
the  simplest  chemical   facts,  namely,  the  absence  of 
alkaline    phosphates   in   the    urine   of   the   herbivora ! 
What  pathologist  has  ever  yet  attempted  to  fix  and  de- 
fine the  notion  of  bad  or  spoiled  food,  in  its  full  signifi- 
cation, by  means  of  a  logical  comparison  with  good  and 
wholesome  food  ?  and  yet  the  former  are  regarded  as 
the  proximate  causes  of  diseased  conditions.     I  readily 


4  METHODS    OF    INVESTIGATION 

admit,  that,  for  such  an  investigation,  chemical  knowl- 
edge is  indispensable  ;  but  the  investigation  itself  has 
no  value  in  reference  to  chemistry,  and  constitutes  no 
object  of  research  for  the  chemist  as  such. 

Want  of  mu-       From  this  state    of  things,  which   depends   on  the 
Uon  tetween  want  of  connection  between  the  labors  of  chemists  and 
.™umphysioi-  tnose  of  physiologists,  it  has  happened,   that  Animal 
Chemistry,  during  the  last  ten  years,  has  gained  little 
more  than  a  more  accurate  knowledge  of  those  com- 
pounds which  the  animal  organism  applies  to  no  further 
purpose  in  its  economy  ;  and  that,  at  the  present  time, 
it  seems  as  if  all  the  wonderful  properties  which  it  ex- 
hibits   were    produced   only   by    means    of    albumen, 
fibrine,  gelatine,  some  cerebral  or  nervous  matter,  and 
a  little  bile.     It  is  universally  felt  that  we  are  as  far 
chemis-  from  a  true  animal  chemistry  as  the  anatomy  of  the 
last  century  was  from  the   physiology  of  the  present 
day.     Indeed,  the  animal  chemistry  of  our  time  cannot 
be  compared  to  modern  anatomy,  since  microscopic  re- 
searches have  established  the   existence   of  structures 
which  had  entirely  escaped  the  earlier  investigators  ;  of 
structures,  as  is  now  known,  on  which  alone  the  func- 
tion of  those  formerly  observed  depends, 
e-  We  know  that  the  aliments  of  all  plants  are  precise- 

™S'  ty  tne  same  ;  but  what  a  multitude  of  forms  do  these 
assume  in  the  organisms  of  different  plants !  The 
same  soil  on  which  we  grow  grain,  beet-root,  or  pota- 
toes, yields  also  tobacco  and  poppies.  In  grain  and 
potatoes  we  have  starch,  —  in  beet- root,  sugar,  —  in  all 
three,  a  certain  amount  of  compounds  containing  sul- 
phur and  nitrogen  ;  in  the  poppy,  a  fat  oil  and  a  series 
of  organic  bases,  —  containing  nitrogen,  but  not  sul- 
phur,—  which  are  not  found  in  other  families  of  plants ; 
in  tobacco,  a  volatile  oil,  —  containing  nitrogen,  —  pos- 
sessed of  basic  or  alkaline  properties. 


IN    ANIMAL    CHEMISTRY.  O 

These  substances,  so  different  in  composition,  are  all 
derived  from  the  same  compounds,  which  nature  sup- 
plies as  food  to  all  plants.  It  is  certain  that  the  differ- 
ences in  the  nature  and  composition  of  these  products 
can  only  be  determined  by  variations  in  the  organiza-  must  depend 
tion  of  the  plants  which  produce  them  ;  for  they  are  ces  of  organ- 
the  visible  signs  of  existing  peculiar  agencies,  and  plants!  ™ 
chemistry,  which  has  succeeded  in  detecting  so  great  a 
variety  in  these  compounds,  belonging  only  to  certain 
vegetable  families,  has  thus,  in  her  department,  sur- 
passed vegetable  anatomy.  But  the  case  is  entirely 
reversed,  when  we  compare  the  progress  of  animal 
anatomy  with  that  of  animal  chemistry.  The  chemical 
relations  which  must  correspond  to  the  different  struc- 
tures and  tissues  are  altogether  unexamined  ;  and  yet 
we  cannot  suppose  otherwise  than  that  the  nature  of  The  varied 

,    .  ,    n    .  .  _  secretions  of 

each  secretion  must  stand  m  a  definite  relation  of  de-  the  animal 
pendence,  in  reference  to  its  composition  and  its  chem- 
ical properties,  with  those  of  the  substance  from  which 
it  is  formed,  or  with  those  of  the  parts  which  are  con- 
cerned in  its  formation. 

If  we  suppose  that  it  is  from  the  blood  that  all  the 
constituents  of  the  animal  body  are  formed,  this  can  must  depend 

,          -,          i  •         •   ,  />          A    -       r  T-ii         on  similar 

only  take  place  in  virtue  of  certain  forces,  which  be-  causes;  not 
long,  not  to  the  blood,  but  to  the  organs  in  which  the  yetstudl 
component  parts  of  the  blood  are  employed  to  produce 
them.  The  direction  and  position,  the  peculiar  arrange- 
ment of  the  elements  of  the  constituents  of  the  blood 
in  the  process  of  nutrition,  are  changed  according  to 
these  seats  of  peculiar  direction  in  the  force  acting  in 
the  body,  which  have  the  same  relation  to  the  blood  as 
the  different  vegetable  families  have  to  the  analogous 
substances  which  they  receive  as  food  from  the  air  and 
the  soil. 

There  is,  probably,  no  fact  more  firmly  established,  Agency  of 


METHODS    OF    INVESTIGATION 


animal  com- 
pounds. 


Agency  of 
ferments 
compared 
with  that 
of  ordinary 
affinity. 


The  trans- 
formation 
caused  by  a 


as  to  its  chemical  signification,  than  this,  that  the  chief 
constituents  of  the  animal  body,  albumen,  fibrine,  the 
gelatinous  tissues,  and  caseous  matter,  when  their  el- 
ements are  in  a  state  of  motion,  that  is,  of  separation, 
exert  on  all  substances  which  serve  as  food  for  men 
and  animals  a  defined  action,  the  visible  sign  of  which 
is  a  chemical  alteration  of  the  substance  brought  in  con- 
tact with  them. 

That  the  elements  of  sugar,  of  sugar  of  milk,  of 
starch,  &c.,  in  contact  with  the  sulphurized  and  nitro- 
genized  constituents  of  the  body,  or  with  the  analogous 
compounds  which  occur  in  plants,  when  these  are  in  a 
state  of  decomposition,  are  subjected  to  a  new  arrange- 
ment, and  that  new  products  are  formed  from  them, 
most  of  which  cannot  be  produced  by  chemical  af- 
finities, is  a  fact,  independent  of  all  theory.  Chem- 
ical affinities  exert  an  influence  on  the  nature  of  the 
new  products,  but  do  not  determine  their  formation. 
The  cause  of  this  is  obvious.  When  an  organic  sub- 
stance is  decomposed  by  a  chemically  active  body,  we 
can,  in  most  cases,  predict  the  nature  and  the  proper- 
ties of  the  new  products  formed  by  its  action.  If  the 
active  chemical  agent  be  an  acid,  all,  or  a  part  of,  the 
elements  of  the  organic  body  combine  to  form  a  base, 
or  to  form  water  ;  if  it  be  a  base,  they  unite  to  form  an 
acid,  that  is,  a  compound,  the  properties  of  which  are 
opposed  to  those  of  the  acting  body,  and  by  which, 
therefore,  its  affinity  is  neutralized.  In  the  processes 
called  fermentation  and  putrefaction,  the  mode  of  ar- 
rangement of  the  elements  of  organic  compounds  is 
of  a  totally  different  kind  ;  because  here  it  is  not  a 
foreign  chemical  attraction,  but  another  cause,  which 
determines  the  new  arrangement.  Now  we  know,  with 
absolute  certainty,  that  the  products  which  may  be  gen- 
erated from  fermentescible  substances  vary,  as  the 


IN   ANIMAL    CHEMISTRY.  7 

state  of  the  ferment^ or  exciter  varies.     The  same  case-  ferment   va- 

,  ,  .    ,       ,  .          .  ries  with  the 

me,  the  same  membrane,  which  determine  the  transpo-  state  of  the 
sition   of  the -elements   of  sugar  so  as   to  form  lactic 
acid,  cause,  in  another  state,  the  same  elements  to  di- 
vide themselves  into  carbonic  acid  and  alcohol,  or  into 
butyric  acid,  carbonic  acid,  and  hydrogen  gas. 

No  one  can  fail  to  perceive  the  significance  of  these  These  princi- 

n  i  i  -i.  !  pies  are  con- 

facts,  m  respect  to  the  understanding  and  the  explana-  cemedinthe 

r>  P   i        •    i  TP        i  •     vital  Pr°- 

tion  of  many  of  the  vital  processes.     If  a  change  in  cesses. 

the  position  and  arrangement  of  the  elementary  mole- 
cules of  animal  compounds  can  exert,  out  of  the  body, 
a  decided  influence  on  a  number  of  organic  substances, 
when  brought  in  contact  with  them ;  if  these  substances 
are  thus  decomposed,  and  new  compounds  formed  of 
their  elements  ;  and  if  we  consider,  that  among  these 
compounds,  namely,  such  as  are  susceptible  of  fer- 
mentation, are  included  all  those  matters  which  consti- 
tute the  food  of  man  and  of  animals,  it  cannot  be 
doubted,  that  the  same  cause  plays  a  most  important 
part  in  the  vital  process  ;  that  it  has  a  great  share  in 
the  alterations  which  nutritious  matters  suffer  when 
they  are  converted  into  fat,  into  blood,  or  into  the  con- 
stituents of  organized  tissues.  We  know,  indeed,  that 
in  all  parts  of  the  living  animal  body  a  change  takes 
place  ;  that  portions  of  living  tissues  are  separated  ; 
that  their  constituents,  Fibrine,  Albumen,  Gelatine,  or 
whatever  they  may  be  called,  give  rise  to  new  com- 
pounds ;  that  their  elements  combine  to  form  new  prod- 
ucts ;  and  in  the  present  state  of  our  knowledge  we 
must  suppose,  that,  by  means  of  this  very  action,  at  all 
points  where  it  occurs,  according  to  its  direction  and 
force,  a  parallel,  or  corresponding,  change  is  effected 
in  the  nature  and  composition  of  all  the  constituents  of 
the  blood  or  of  the  food  which  come  into  contact  with 
them  ;  and  that,  consequently,  the  change  of  matter  is  The  change 

J  '  of  matter  is 


8 


METHODS    OF    INVESTIGATION 


itself  a  chief  cause  of  the  transformations  which  the 
constituents  of  the  food  undergo,  and  also  a  condition 
of  the  process  of  nutrition.  We  must  further  admit, 
that  with  every  modification  produced  by  a  cause  of 
disease  in  the  process  of  transformation  of  an  organ, 
of  a  gland,  or  of  one  of  their  constituents,  the  action 
of  this  organ  on  the  blood  conveyed  to  it,  or  on  the 
nature  of  the  resulting  secretion,  must,  in  like  man- 
ner, be  changed  ;  that  the  effect  of  a  number  of  reme- 
.  dies  depends  on  the  share  which  they  take  in  the 
change  of  matter ;  and  that  such  remedies  exert  an 
influence  on  the  quality  of  the  blood  or  of  the  food, 
chiefly  in  this  way,  that  they  alter  the  direction  and 
force  of  the  action  taking  place  in  the  organ,  which 
action  they  may  accelerate,  retard,  or  arrest. 

The  intermediate  members  of  the  almost  infinite  se 
ries  of  compounds  which  must  connect  Urea  and  Uric 
acid  with  the  constituents  of  the  food  are,  with  the 
exception  of  a  few  products  derived  from  the  bile, 
almost  entirely  unknown  to  us;  and  yet  each  individ- 
ual member  of  this  series,  considered  by  itself,  inas- 
much as  it  subserves  certain  vital  purposes,  must  be 
of  the  utmost  importance  in  regard  to  the  explanation 
of  the  vital  processes,  or  of  the  action  of  remedies. 
The  chief  constituent  of  bile  is  a  crystallizable  com- 
pound ;  and  no  physiologist  now  denies,  that  it  is  in- 
dispensable for  the  process  of  digestion. 

Were  we  to  discover  in  the  organism  certain  ar- 
rangements by  which  a  permanent  electrical  current 
must  be  determined  at  all  points,  could  any  one  doubt 
that  such  a  current  must  take  a  share  in  the  vital  pro- 
cesses ?  Or  if  it  were  proved,  that  from  the  constit- 
uents of  the  food  of  all  animals,  among  other  com- 
pounds, organic  bases  are  formed,  which  in  their  chem- 
ical nature  resemble  caffeine  or  quinine,  or  any  other 


IN    ANIMAL    CHEMISTRY.  y 

organic  base ;  if  such  compounds  could  be  detected 
everywhere,  in  all  parts,  or  only  in  certain  parts,  of 
the  organism,  should  we  not  have  advanced  a  step 
nearer  to  the  explanation  of  the  action  of  caffeine  or 
of  quinine  ? 

About  ten  years  since,  the  ultimate  analysis  of  or- 
ganic bodies  furnished  physiology  with  a  result  highly 
important,  in  order  to  the  easy  understanding  of  the  Erroneous 

,.  A    .  .  ,  ,         deductions 

digestive  or  nutritive   process,  by  demonstrating,  that  from  the  sup- 
fibrine,  albumen,  and  caseine  have  the  same  compo-  fyTn  compo- 
sition.    Misled  by  this   result,  many  chemists  thought  fibdne^aitm- 
that  the  chief  problem  to  be  solved  by  chemistry  was  Sseine"1 
to  ascertain,  by  ultimate  analysis,  the  composition,  in  * 

100  parts,  of  all  the  constituents  of  the  body ;  and  thus 
many  were  induced  to  act  on  each  of  these  constitu- 
ents, without  a  more  minute  study  of  its  chemical  rela- 
tions and  its  properties,  with  alcohol,  ether,  and  acids ; 
and  with  the  aid  of  the  known  resources  of  organic 
analysis,  to  determine  the  percentage  of  carbon,  nitro- 
gen, hydrogen,  and  oxygen.  They  believed  that  they 
had  thus,  by  means  of  these  numerical  results,  done  a 
real  service  to  physiology,  although  the  only  addition 
thus  made  to  the  name  of  the  substance  analyzed  was 
an  empty  formula,  of  the  accuracy  of  which  there  was  ^__ 
no  evidence  whatever.  Now  that  we  have  been  for  No  progress 

_  _  has  been 

ten    years  in   possession  of  these  formula?,  every  one  made  by  the 

,  .  ,  ,  aid  of  mere 

must  perceive  that  we  have  made  no  real  progress,  formulae. 
The  cause  of  this  is  obvious  to  all  who  know  the  true 
value  of  ultimate  analysis.  Ultimate  analysis  is  a 
means  of  acquiring  knowledge,  but  is  not  itself  that 
knowledge.  Even  supposing,  what  no  one  will  seri- 
ously maintain  with  regard  to  the  constituents  of  the 
animal  body,  that  analysis  had  made  us  acquainted 
with  the  exact  proportions  in  which  their  elements  are 
united  together,  yet  this  knowledge  gives  us  not  the 


10  METHODS    OF    INVESTIGATION 

The  mode  of  least  information  as  to  the  arrangement  of  these  ele- 

arrangement  ,,  •  i  •    i      ^i  -i 

of  the  eie-      ments,  or   the   way  in   which  they   group  themselves. 

"ssentiaf  * ie  under  the  influence  of  chemical  agencies.  Now  it  is 
the  knowledge  of  both  these  things  together  which 
alone  can  lead  us  to  definite  views  as  to  the  part  which 
these  compounds  play  in  the  vital  processes,  or  the 
changes  to  which  they  are  subjected  up  to  the  period 
of  their  expulsion  from  the  body ;  and  this  is  essen- 
tially the  problem  which  Chemistry  has  to  solve  in 
reference  to  the  vital  process. 

Ultimate  Ultimate  analysis,  by  itself,  has  this  peculiarity,  that 

analysis  is        .  „ 

notsuffi-        in  the  case  of  very  complex  substances  it  cannot  se- 
•  cure  the  chemist  against  errors,  because  there  is  no 

other  control  for  the  accuracy  of  the  analysis  than  the 
analysis  itself;  and  because  the  errors  are  equal  at 
different  times,  and  escape  notice  when  we  cannot 
change  the  methods  of  determining  the  individual  ele- 
ments. Now  there  is  as  yet  no  means  of  determining 
the  weight  of  carbon  otherwise  than  in  the  form  of 
carbonic  acid,  or  that  of  hydrogen  otherwise  than  in 
the  form  of  water. 

it  must  be          The  only  way  to  attain  an  accurate  expression  for 
by^Ktidy  the  composition  of  those  substances,   which,  like  the 

of  products  of  .  „    ,  'iii 

decomposi-  constituents  of  the  animal  body,  contain  a  very  large 
number  of  elementary  molecules  in  the  complex  atom 
of  the  compound,  is  to  endeavour  to  resolve  it  into 
two  or  more  less  complex  compounds,  and  to  com- 
pare the  composition  and  the  amount  of  these  products 
with  those  of  the  body  from  which  they  have  been  de- 
rived. 

Example  In   this   respect,   the  history   of  Salicine  offers  the 

from  the 

history  of       most  striking  instance,  and  may  serve  to  convince  ev- 

Salicine.  ..  . 

ery  one  how  little  can  be  attained  m  questions  of  this 
kind  by  means  of  ultimate  analysis  alone.  Five  of 
the  most  accurate  and  conscientious  chemists  endeav- 


IN   ANIMAL    CHEMISTRY.  11 

oured,  with  all  the  dexterity  which  they  are  known  to 
possess,  to  fix  the  relative  proportion  of  the  elements 
in  salicine  (a  body  of  a  far  less  complex  nature  than 
animal  substances),  but  without  the  slightest  success, 
until  a  method,  discovered  by  Piria,  of  resolving  sali- 
cine into  two  other  compounds,  at  once,  and  without 
further  exertion,  removed  the  difficuly.  For  each  com- 
pound there  is  but  one  correct  formula,  but  there  are 
innumerable  formulae  which  approach  the  truth ;  and 
it  can  only  occur  by  the  rarest  chance  that  a  chemist 
succeeds  in  discovering  the  true  formula  of  a  com- 
pound from  the  results  of  its  ultimate  analysis.  But 
the  confidence  which  we  repose  in  the  dexterity  of  a 
chemist  can  never  furnish  a  foundation  for  theoretical 
views ;  and  it  has  not  yet  been  the  lot  of  any  analyst 
to  stand*  free  from  error  in  this  respect.  Those  chem- 
ists who  have  enriched  the  science  with  the  greatest 
number  of  true  formulae  have  only  attained  this  suc- 
cess by  means  of  their  own  erroneous  formulae. 

The  method  just  pointed  out  for  attaining  an  accu-  Erroneous 

application 

rate  formula  has  not,  however,  escaped  the  notice  of  of  this 
those  who  regard   ultimate  analysis   as   the    last   and 
highest  object  of  a  chemical  investigation  ;  but  the  ut- 
terly fallacious  application  of  this  method  has  misled 
them  into  far  greater  errors  and  inaccuracies. 

They    believed,    for   example,    in    studying    a    sub-  Fallacious 
stance,  that  they  had  fulfilled  all  the  requisite  condi-  efiuations- 
tions  when  they  had  succeeded  in  representing  its  de- 
composition in  the  form  of  an  equation,  without  caring 
whether  the  formulae  which  made  up  the  equation  rep- 
resented actual  substances,  or  existed  merely  in  their 
imagination. 

The  following  example  will  serve  to  place  in  a  clear 
light  what  is  here  intended. 

When  we  dissolve   uric  acid  in  diluted  nitric  acid,  illustration 

7  from  the 


12  METHODS    OF    INVESTIGATION 

action  of  carbonic  acid  and  nitrogen  gases  are  given  off  in  equal 
cm  uric*  volumes,  and  we  obtain  an  acid  solution,  which,  if 
neutralized  by  baryta,  leaves,  on  evaporation,  a  mass 
soluble  in  alcohol,  with  the  exception  of  the  nitrate 
of  baryta.  The  products  of  the  decomposition  of  uric 
acid  by  nitric  acid  are,  therefore,  carbonic  acid,  nitro- 
gen, and  the  above-mentioned  residue  soluble  in  alco- 
hol. Now  it  is  evident,  that  if  we  ascertain  the  weight 
of  the  uric  acid  and  that  of  the  residue,  the  compo- 
sition of  the  latter,  and  the  proportions  by  weight  of 
the  carbonic  acid  and  nitrogen  disengaged,  the  decom- 
position may  now  be  expressed  in  a  perfectly  correct 
equation,  on  one  side  of  which  we  have  the  formulae 
of  a  certain  quantity  of  nitric  acid  and  water,  and  on 
the  other,  the  formulae  of  the  product,  soluble  in  alco- 
hol, of  carbonic  acid,  and  of  nitrogen.  We-  should 
thus  have  performed  a  series  of  laborious  analytical 
operations,  but  no  investigation  of  the  slightest  scien- 
tific value ;  for  every  one  knows  that  the  product  solu- 
ble in  alcohol  consists  of  at  least  five  different  sub- 
stances, the  relative  quantity  of  which  varies  with  the 
temperature  and  the  concentration  of  the  acid.  If  we 
had  mixed  the  solution  of  this  product  with  a  salt  of 
lead,  we  should  have  obtained  one  precipitate;  with 
subacetate  of  lead,  a  second  ;  and  by  subsequently  ad- 
ding ammonia,  a  third  ;  which,  after  we  had  ascertained 
their  composition,  would  have  enabled  us  to  insert  in 
the  equation,  instead  of  the  formula  of  the  original 
product,  two  or  three  new  formula?.  The  equation 
would  still  have  continued  accurate,  but  it  would  have 
contained  merely  imaginary  values,  and  not  the  for- 
mulae of  real  substances,  existing  independently  of  the 
numbers. 
Example  If  we  compare  with  this  example  the  investigation 

from  the  pro- 

teinecom-     of  the   products  which  albumen,   fibrine,  and  caseine 

pounds. 


IN    ANIMAL    CHEMISTRY.  13 

yield,  when  acted  on  by  strong  alkalies,  we  shall  im- 
mediately perceive,  that  the  equations  employed  in 
books  and  treatises  to  represent  the  changes  which 
occur,  as  well  as  the  formulae  of  the  products  assumed 
in  these  equations,  have  been  obtained  entirely  by  this 
fallacious  method,  and  that  these  statements  are  utter- 
ly worthless  for  our  purpose. 

Mulder,  in  his  "  Versuch  einer  physiologische  Che-  Mulder'* 
mie,"  Part  IV.  p.  321,  says  :  —  "  When  white  of  egg,  ec 
or  any  other  proteine  compound,  is  boiled  with  potash, 
entire  decomposition  takes  place.     The  products  of  this  representing 

,      .        ,     p  ,  .         the  decompo- 

reaction  are  certainly  not   derived   from  the   proteine  sition  of  pro- 
alone,  but  still  some  of  them  must  be  regarded  as  con-  bate,  7 
stituents  of  that  substance.     These  are  : 

C.  H.  N.     O. 

2  eq.  Leucine         ...          24  48  4  8 

Protide*    ....      26  36  4  8 

Erythroprotide        .         .          26  32  4  10 


Ammonia  .         .         .      —        24        8 

Carbonic  Acid        .  '      .  2        —      —      4 

Formic  Acid  .        .        2  2—3 


2  eq.  Proteine  +  9  eq.  water  =       80       142      20     33  " 

A  glance  at  this  equation  is  sufficient  to  show,  that 
the  agreement  is  as  complete  as  possible.  On  one  side, 
we  have  the  elements  of  proteine  and  of  water,  on 
the  other,  six  products  of  decomposition,  the  sum  of 
the  elements  being  exactly  equal  on  both  sides  ;  and 
yet  a  repetition  of  the  experiment  on  which  the  equa- 
tion is  founded  teaches  us  that  the  whole  explanation  -^  quiu  faliu. 
is  utterly  fallacious.  For  the  chief  product  of  this  de- 
composition is  a  compound  (possibly  more  than  one 
compound)  not  precipitable  by  salts  of  lead  ;  there  is 

*  Erythroprotide  is  that  product  which  is  precipitated  by  neu- 
tral acetate  of  lead  ;  pro  tide,  that  which  is  thrown  down  by  ^sub- 
acetate  of  lead. 

2 


C10US. 


14  METHODS    OF    INVESTIGATION 

produced  no  formic  acid,  but  oxalic  acid,  as  well  as 
valerianic  and  butyric  acids ;  and  in  the  case  of  fibrine, 
caseine,  and  the  albumen  of  the  serum  of  blood,  there 
is  formed  a  crystallizable  body,  Tyrosine  (I  give  this 
name  to  the  substance  described  by  me  in  the  "  Annalen 
der  Chemie  und  Pharmacie,"  Vol.  LVII.  p.  127),  in  all, 
therefore,  five  members,  which  are  wanting  in  the 
equation.  Moreover,  according  to  the  above  equation, 
100  parts  of  white  of  egg  should  yield  30  parts  of 
leucine,  whereas,  in  reality,  we  can  obtain  hardly  2  per 
cent,  of  that  compound, 
imperfect  no-  Such  explanations  as  the  above  are  founded  on  an 

tions  of  the     .  „  .  „    .  . 

true  province  imperfect  conception  of  the  true  object  of  a  chemical 

of  chemical     .  .  ,       . 

research.  investigation ;  and  when  the  same  author,  in  order  to 
support  his  view,  that  the  iron  in  the  coloring  matter  of 
the  blood  exists  in  that  compound  as  metallic  iron  (which 
amounts  to  the  same  thing  as  saying,  for  example,  that 
sugar  contains  carbon  in  the  form  of  diamond),  as- 
serts, that  by  leaving  the  red  matter  of  the  blood  in 
contact  with  oil  of  vitriol,  and  then  adding  water,  he 
obtained  hydrogen  gas ;  or  when  he  states,  in  order  to 
have  a  source,  peculiar  to  himself,  of  the  nitrogen  in 
plants,  that,  according  to  his  experiments,  certain  con- 
stituents of  peat  and  brown  coal  possess  the  property 
of  condensing  the  nitrogen  of  the  air  and  converting  it 
into  ammonia,  or  some  similar  compound  of  nitrogen, 
these  statements  are  so  many  irrefragable  proofs  that 
he  entertains  erroneous  views  as  to  the  true  object  of 
scientific  researches.  Without  possessing  the  gift  of 
prophecy,  we  may  safely  predict  that  we  shall  have,  in 
a  few  years,  in  place  of  the  formulae  which  he  has 
given  for  animal  compounds,  and  which  he  regards  as 
for  ever  established,  entirely  different  formula.  It  will 
fare  with  these  analyses  as  with  those  which  he  has 
made  of  vegetable  mucilage,  of  pectine,  of  glycocoll  * 


IN    ANIMAL    CHEMISTRY.  15 

(sugar  of  gelatine),  and  other  substances,  for  the  accu- 
racy of  which  the  dexterity  of  the  chemist  is  for  a  time 
regarded  as  a  guarantee,  but  which  cease  to  be  consid- 
ered accurate  when  the  substances  analyzed  become 
the  subject  of  more  exact  investigation. 

When  such  fallacious  principles  and  methods  of  in-  Erroneous 

.     ,    ,  i  •      i   theories 

vestigation  are  accompanied  by  erroneous  theoretical  impede 
views,  which,  while  they  refuse  admission  to  the  most  pl 
convincing  evidence  of  the  truth,  are  defended  with  a 
violence  and  obstinacy  proportioned  to  the  feebleness 
of  these  views,  the  field  of  research  becomes  a  stage 
on  which  the  most  selfish  passions  are  brought  into  ac- 
tion ;  but,  under  such  circumstances,  progress  is  out  of 
the  question. 

A  theoretical  view  in  natural  science  is  never  abso-  A  theoretical 
lutely  true,  it  is  only  true  for  the  period  during  which  trueVor  the y 

....,"  T  .        period. 

it  prevails ;  it  is  the  nearest  and  most  exact  expression 
of  the  knowledge  and  the  observations  of  that  period. 
In  proportion  as  our  knowledge  is  extended  and  changed, 
this  expression  of  it  is  also  extended  and  changed,  and 
it  ceases  to  be  true  for  a  later  period,  inasmuch  as  a 
number  of  newly  acquired  facts  can  no  longer  be  includ- 
ed in  it.  But  the  case  is  very  different  with  the  so-called 
proteine  theory,  which  cannot  be  regarded  as  one  of  the  The  theory 

...  .  ,     .  j   of  proteine 

theoretical  views  just  mentioned,  since,  being  supported  never  ex- 

,  .   .        pressed  the 

by  observations  both  erroneous  in  themselves  and  mism-  knowledge 
terpreted  as  to  their  significance,  it  had  no   foundation  period. 
in  itself,  and   was  never  regarded,  by  those  intimately 
acquainted  with  its  chemical  groundwork,  as  an  expres- 
sion of  the  knowledge  of  a  given  period. 

In  the  "  Annalen  der  Chemie  und  Pharmacie"  (Vol.  Defects  of 
LVIII.  pp.  129  et  seq.),  Laskowski  has  already  fully 
developed  the  analytical  evidence  which  bears  against 
this  theory,  and  we  may  here  direct  attention  to  the 
defects  of  the  theoretical  notions  on  which  it  rests,  or, 
more  properly,  does  not  rest. 


16  METHODS    OF    INVESTIGATION 

Supposed  The  results  of  the  ultimate  analysis  of  fibrine,  albu- 

"oniposition  men,  and  caseine  attracted,  ten  years  ago,  the  attention 
aibumen%nd  due  to  them  ;  since  they  seemed  to  prove  that  these  three 
bodies  had  the  same  composition,  the  notions  enter- 
tained concerning  the  process  of  digestion  and  nutrition 
acquired  a  great  degree  of  simplicity  ;  these  results 
contributed  to  demonstrate  the  value  of  chemical  com- 
position as  an  element  in  the  discussion  of  physiologi- 
cal questions. 

But  this  result,  derived  from  ultimate  analysis,  had 
two  disadvantages.  The  first  was,  that  we  were  dis- 
posed to  believe  that  identity  of  composition  in  the  sul- 
phurized and  nitrogenized  constituents  of  food  and 
those  of  the  blood  was  indispensable  for  the  understand- 
not  necessary  ing  and  explanation  of  the  digestive  process.  But, 
pianation  of  theoretically,  this  identity  of  composition  is  not  indis- 
prooiM.  e  pensable ;  it  only  facilitated  the  investigation.  When 
a  chemical  attraction  causes  the  formation  of  a  com- 
pound, it  is,  in  regard  to  the  chemically  active,  or  at- 
tracting, body,  quite  indifferent  whether  the  atoms 
which  it  attracts  form  a  group,  bound  together  by  their 
mutual  attractions,  or  are  simply  arranged  near  each 
other,  without  being  combined.  To  produce  the  com- 
pound, it  is  only  necessary  that  the  attractive  force 
should  be  more  powerful  than  the  forces  which  oppose 
its  manifestation,  that  is,  the  formation  of  the  new 
compound.  If  the  attractive  force  preponderates,  the 
attracted  elements  enter  into  the  new  combination,  and 
this,  whether  they  have  been  previously  arranged  in  one, 
two,  or  three  compound  molecules  or  groups ;  and  the 
result  is  exactly  the  same  as  if  the  attracting  body  had 
combined  with  one  group  of  combined  atoms. 
Example.  Hydrocyanic  acid,  for  example,  mixes  in  every  pro- 

portion with  water,  jujst  as  many  liquids  do,  which  may 
be  mixed  without  forming  a  chemical  combination  ;  but 


IN    ANIMAL    CHEMISTRY.  17 

when  the  atoms  of  water  and  of  hydrocyanic  acid  are 
in  a  certain  degree  of  proximity,  and  we  add  hydro- 
chloric acid  to  the  mixture,  the  mixture  acts  as  if  it  were 
a  compound  of  ammonia  with  formic  acid.  The  hydro- 
chloric acid  is  converted  into  sal  ammoniac,  while  the 
remaining  elements  unite  to  produce  formic  acid. 
Here  the  nitrogen  of  the  hydrocyanic  acid  and  the  hy- 
drogen of  the  water,  two  elements  belonging  to  two 
entirely  distinct  compounds,  act,  in  reference  to  the  hy- 
drochloric acid,  as  if  they  were  combined  to  form  the 
compound  atom  which  we  call  ammonia. 

In  like  manner,  the  formation  of  the  blood  constitu- 
ents would  have  equally  admitted  of  explanation,  and 
would  have  been  equally  well  explained,  even  had  the 
food  contained,  instead  of  one  sulphurized  and  nitrogen- 
ized  constituent,  two  or  three  compounds,  in  one  of 
which  was  found  the  sulphur,  in  the  second  the  nitro- 
gen, arid  in  the  third  the  carbon  required  to  make  up 
the  sum  of  the  elements. 

Under  the  influence  of  this  idea  of  the  necessity  of  Fibrine  dif- 

.  i        .        .        ,         i          •      ••  .  .  „   ,  .  fers  in  corn- 

identity  in  the  chemical  composition  of  the  constituents  position  from 

of  the  blood  and  those  of  the  food,  Mulder  was  first  caseine.  ar 

led  to  assume,  in  fibrine,  the  same  relative  proportion 

of  atoms    of  nitrogen  and  carbon  as  in  albumen  and 

caseine,    in  spite    of  the  analyses  of  Gay-Lussac  and 

Thenard,  of    Michaelis,  of  Vogel,  and  of  Fellenberg, 

all  of  which  indicated  a  larger  proportion  of  nitrogen 

in  fibrine  ;  and  his  example,  or  rather,  the  influence  of 

his  authority,  reacted  on  several  of  those  who  followed 

him,  who  were  so  far  misled  as  to  reject  as  inaccurate 

the  greater  number  of  their  own  accurate  analyses,  and 

to  give  the  preference  to  those  which  were  defective. 

The  second  and  far  more  serious  disadvantage  was  ^r/™e^s 
the  erroneous  view  of  the  chemical  constitution  of  the  ^ced  from 

their  sup- 

three  animal  substances  just  named,   which   chemists  posed  iden- 
2* 


18  METHODS    OF    INVESTIGATION 

believed  themselves  justified  in  deducing  from  the  iden- 
tity of  their  composition  in  100  parts. 
How  are  the        The  question,  in  what  way  the  elements  of  fibrine, 

elements  of        n  ,  ,     . 

these  com      albumen,  and  caserne  are  arranged,  is  one  of  the  most 
ranged8?""      interesting  and  important  in  Animal  Chemistry.     These 
three  bodies  contained  (at  that  time  this  was  still  be- 
lieved in  the  case  of  fibrine)  an  equal  amount  of  car- 
bon, nitrogen,  hydrogen,  and  oxygen,  while  there  was 
great  difference  in  their  physical  properties.     But  we 
isomeric        had  been   long   familiar   with    groups   of  compounds, 

compounds          ,  .    ,  .  ,  „          .  , 

Jong  known,  which,  with  a  perfect  identity  of  composition,  exhibit 
the  most  marked  differences  in  their  properties;  this 
supposed  identity  of  composition  was  not,  therefore, 
surprising.  In  all  isomeric  substances,  more  exact  re- 
search had  demonstrated  that  their  elements  were  dif- 
ferently arranged,  and  that,  consequently,  their  chemical 
constitution  was  to  the  full  as  different  as  were  their 
physical  properties.  Although  their  composition  in 
100  parts  was  the  same,  yet  their  atomic  weight,  or  the 
products  of  their  decomposition,  or  their  density  in  the 
state  of  vapor,  was  different ;  the  variation  in  their 
chemical  constitution  corresponded  to  that  of  their 
physical  properties. 

But  isomer-        What,  now,  according  to  these  previous  observations, 

ism  was  not  .  _    .  ...     .  .         .        . 

supposed  to  was  the  cause  of  the  great  dissimilarity  in  the  proper- 
explanation  ties  of  the  above-mentioned  animal  substances?  If 
their  elements  were  differently  arranged,  or  the  prod- 
ucts of  their  decomposition  or  transformation  different, 
this  formed,  of  course,  no  obstacle  to  the  probable  con- 
version of  one  into  the  other,  of  caseine  or  fibrine 
into  albumen,  or  of  albumen  into  caseine  and  fibrine, 
since  the  study  of  isomeric  substances  had  taught  us, 
that  in  many  cases,  even  where  the  difference  of  chem- 
ical constitution  was  very  great,  such  transformations 
of  one  into  another  actually  occur.  All  this  was  left 


IN    ANIMAL    CHEMISTRY.  19 

unexplored.     The   chemist  who   first   entered   in    this 
field  of  research,  which  promised  so  abundant  a  har-  Aiithesesub- 
vest,  assumed,  on  the  strength  of  the  most  defective  siTppos^dTo6 
experiments,  that  in  these  three  substances  the    four  grouper  eie- 
above-named  elements  were  combined,  exactly  in  the  ments' 
same  way  in  all,  to  form  a  group,  which  group  consti- 
tuted a  distinct  substance,  capable  of  being  isolated,  to 
which  the  name  of  proteine  was  given.     Assuming  the  called  pro- 

•  •  t*    i  •  i  -n   teine, 

chemical  constitution  of  this  group  as  the  same  in  all 
three  bodies,  what  was  now  the  origin  of  so  great  a 
difference  in  properties  as  they  presented  ?  The  cause 
of  this  difference  was  sought  for  in  a  fifth  element,  or 
in  a  second  group. 

It  was  found,  namely,  that  all  these  animal  substan-  combined 

-  .  with  various 

ces  contain  a  certain  amount  of  sulphur ;  it  was  as-  proportions 

.  .      of  sulphur 

sumed,   that   some  of  them  contained  also  a  certain  andphospho- 
amount  of  phosphorus  ;  and  the  variation  in  their  prop- 
erties was  ascribed  to  the  presence  of  this  sulphur,  or 
sulphur  and  phosphorus.     (The  existence  of  phospho-  jjjj^jj^^ 

rus,  as  an  essential  element  of  these  substances,  has  shown  to  con- 
tain phospho- 

not,  however,  been  in  any  way  established.)  In  this  rus- 
way  an  organic  radical,  or  a  body  analogous  to  organic 
radicals,  was  created  ;  a  body  formed  by  the  combina- 
tion of  twelve  hundred  elementary  atoms,  a  group  of 
twelve  hundred  atoms,  the  physical  character  of  which 
was  determined  by  the  addition  of  one  or  more  atoms 
of  sulphur,  or  of  sulphur  and  phosphorus.  To  support 
this  view,  a  property  was  imagined,  which  a  compound 
of  sulphur  could  not  possibly  exhibit.  The  sulphur, 
which  in  these  compounds  caused  such  striking  differ- 
ences, was  as  loosely  combined  with  the  proteine  as 
we  find  it  in  a  mixture  of  iron  filings  or  sawdust  with 
sulphur.  It  was  supposed,  that  when  these  substances 
are  acted  on  by  an  alkali,  the  sulphur  was  detached 
from  the  proteine,  just  as  easily  as  if  it  had  not  been 


20  METHODS    OF    INVESTIGATION 

combined  with  it ;  it  dissolved  in  the  form  of  sulphide 
of  potassium  and  hyposulphite  of  potash  ;  the  proteine 
was  thus  set  free,  and  dissolved  also  in  the  excess  of 
alkali ;  and  when  this  alkaline  liquid  was  neutralized 
by  an  acid,  the  fundamental  constituent  of  these  animal 
substances,  the  proteine,  was  obtained  in  the  form  of  a 
Supposed  ox-  gelatinous  precipitate.  The  idea  of  the  sulphide,  or 
teine,  &c.  of  the  sulpho-phosphide,  of  proteine  led  at  once  to  a 
series  of  oxides  of  proteine,  to  a  multitude  of  imagi- 
nary substances,  to  which  was  now  ascribed,  as  of  old  to 
phlogiston  in  chemical  processes,  the  function  of  deter- 
mining and  effecting  all  the  changes  which  occur  in 
the  vital  process. 

Let  us  now  see  to  what  truths  this  supposition  has 
led,  and  how  it  explains  the  differences  in  the  proper- 
ties of  the  animal  substances.     In  the  latest  work  of 
Composition  Mulder  above  quoted  (p.  316),  the  constitution  of  the 

of  animal  . 

substances     proteine  compounds  is  represented  as  follows  :  — 

according  to 

Mulder.  "  eq.  eq. 

Crystal  line  humor  contains  for  15  Proteine  1  Sulphur 
Caseine  "         10        "         1      " 

Vegetable  gelatine         "         10        "         2      "       eq. 
Albumen  of  eggs  "         10         "         1      "    &  1  Phosphorus 

Fibrine  "         10        "         1      "        1         " 

Albumen  of  blood         "        10        "        2     "        1 

We  have  now  reached  the  ultimate  object  of  this  the- 
ory ;  and  the  question,  What  insight  has  it  afforded  ? 
is  answered  by  a  glance  at  the  above  table. 
Albumen  of        The  albumen  of  the  blood,  the  properties  of  which 

blood  said  to  * 

differ  from  ai-  coincide  so  closely  with  those  of  the  albumen  of  eggs, 

bumen  of 

eg?s,  chemically  as  well   as  physically,    contains   twice    as 

much  sulphur.  Here  similarity  of  properties  accom- 
panies a  difference  in  composition  ;  and  from  this  we 
can  draw  no  other  conclusion  than  this,  that  the  sul- 
phur, the  amount  of  which  varies,  has  no  influence  on 
these  properties. 


IN    ANIMAL    CHEMISTRY.  21 

But  what  is  the  cause  of  the  great  difference  between  while  fibrine 
the  properties  of  fibrine  and  those  of  the  albumen  of  competition6 
eggs  ?     Is  it  sulphur  or  phosphorus  ?     No.     These  sub-  eLaslbume 
stances  contain  (according  to  Mulder),  the  same  quan- 
tities of  proteine,  sulphur,  and  phosphorus. 

Such  is  the  progress  which  Animal  Chemistry  has  Such  views 
made  in  eleven  years  in  regard  to  the  chemical  consti-  real  progress, 
tution  of  the  blood  constituents  ;  we  know  as  much  of 
it  now  as  we  did  forty  years  since  ;  not  to  mention  that 
the  assumption  of  the  presence  of  phosphorus  in  albumen 
and  fibrine,  an  assumption  resting  on  the  most  frivolous 
experiments,  renders  the  explanation  of  the  transforma- 
tion of  the  caseine  of  milk  into  blood  utterly  impossible. 

Any  one,  who  will  take  the  trouble  to  prepare  the  so-  sulphur  ex- 
called  proteine  according  to  the  directions  of  Mulder,  form'sYiTani- 
must  immediately  perceive  that  sulphur  is  contained  in  |^1.subBtan" 
fibrine,  albumen,  and  caseine  in  two  distinct  forms  of 
combination. 

If  we   suppose  these  bodies  to  consist  of   several  in  the  form 

«  «  ...  in  which    it 

groups  of  atoms,  of  which  groups  two  contain  sulphur,  occurs  in  cys- 
the  action  of  alkalies  on  them  points  out  that  the  sul- 
phur in  one  of  these  compounds  exhibits  the  same  re- 
lations as  the  sulphur  in  cystine  ;  the  sulphur  of  this 
compound  combines  with  potassium,  while  it  is  re- 
placed by  the  oxygen  of  the  potash  ;  but  the  other 
compound  of  sulphur  remains  unchanged,  and  its  sul- 
phur exhibits  the  relations  of  that  contained  in  taurine.  and  in  tau- 
We  observe,  moreover,  that  the  former  (the  more  easily 
decomposed)  of  these  sulphur  compounds  preponder- 
ates in  the  albumen  of  the  blood ;  the  latter  in  caseine. 
Any  one  who  reads  the  note  which  I  published  thir- 
teen months  ago  in  the  "  Annalen  der  Chemie  und 
Pharmacie  "  (Vol.  LVII.  p.  133),  on  these  questions, 
will  admit,  that  it  was  impossible  to  use  greater  for- 
bearance in  pointing  out  to  the  author  of  the  pro- 


22  METHODS    OF    INVESTIGATION. 

teine  theory  the  error  into  which  he  had  fallen  than  I 
then  did,  while  I  afforded  him  the  opportunity  of  re- 
peating his  experiments.  The  result,  however,  was 
the  publication  of  his  recent  pamphlet,  a  work  which  1 
shall  not  further  notice,  preferring  to  leave  the  facts, 
as  now  ascertained  and  generally  admitted,  to  speak 
for  themselves. 

Results  of  It  now  appears,  as  the  result  of  the  more  accurate 
searches6"  investigations  of  Laskowski,  Ruling,  Verdeil,  Walther, 
Larger  and  Fleitmann,  that  the  amount  of  sulphur  present  in 

amount  of         ,        ,  ,        ,  .  . 

sulphur  pres-  the  blood  constituents  is  three  times,  in  many  cases 
four  times,  as  great  as  the  apparently  well-established 
analyses  of  the  author  of  the  proteine  theory  had  in- 

Proteinecan-  dicated.     It  further  appears,  that  a  body,  destitute  of 

not  be  ob-  J  ' 

tained  by       sulphur,  and  having  the  composition  of  proteine,  is  not 

Mulder's  •      •    '   *  i 

methods.  obtained  by  the  methods  given  by  Mulder  ;  that  fibrme 
differs  in  composition  from  albumen  ;  that  the  albumen 
of  eggs  contains  not  less,  but  more,  sulphur  than  the 
albumen  of  the  blood,  which  sufficiently  explains  the 
disengagement  of  hydrosulphuric  acid  in  the  exper- 
iments made  with  the  former  on  artificial  digestion. 

Products  of    The  study  of  the  products  which  caseine  yields  when 

the  decompo-  .  iiiii-  •  j        /»       i  •    i_ 

sition  of  case-  acted  on  by  concentrated  hydrochloric  acid,  ot  which, 
and  tehe  blood  as  Bopp  has  found,  Tyrosine  and  Leucine  constitute 
the  chief  part,  and  the  accurate  determination  of  the 
products  which  the  blood  constituents,  caseine  and  gela- 
tine, yield  when  oxidized,*  among  which  the  most  re- 
markable are  oil  of  bitter  almonds,  butyric  acid,  alde- 
hyde, butyric  aldehyde,  valerianic  acid,  valerohitrile. 
and  valeracetonitrile,  have  opened  up  a  new  and  fertile 
field  of  research  into  numberless  relations  of  the  food 
to  the  digestive  process,  and  into  the  action  of  remedies 
in  morbid  conditions  ;  discoveries  of  the  most  wonder- 

*  See  Appendix  A. 


CONSTITUENTS   OF    THE    JUICES   OF   FLESH.  23 

ful  kind,  which  no  one  could  have  even  imagined  a  few 
years  ago  ;  and  the  investigation  which  I  now  proceed 
to  describe  will,  I  trust,  contribute  to  excite  the  hopes 
of  chemists  and  of  physiologists,  and  encourage  them 
to  direct  their  efforts,  more  than  they  have  hitherto 
done,  towards  this  department  of  science. 


SECTION  II. 

On  the  Constituents  of  the  Juices  of  Flesh. 

IT  has  long  been  known  that  the  flesh  of  newly-killed  Acid  reaction 
animals  reddens  blue  litmus  paper,  while  nothing  cer-  of  flesh!"10' 
tain  is  known  as  to  the  nature  of  the  free  acid  which 
causes  this  reddening.     Berzelius,  in  his  detailed  in- 
vestigation of  the  juice  of  flesh,  observes  on  this  sub- 
ject as  follows  :  *  — 

"  When  the  liquid"  (obtained  by  pressure  from  the  Opinions  of 
muscular  substance),  "out  of  which  the  albumen  and 
the  coloring  matter  have  been  coagulated,  is  evaporated 
after  filtration,  it  leaves  a  yellowish-brown  extract,  of 
which  alcohol  takes  up  the  half  or  more  with  a  yellow 
color.  After  the  evaporation  of  this  solution  there  is 
left  an  extract-like  mass,  mixed  with  crystals  of  com- 
mon salt,  which  has  a  strong  acid  reaction,  and  not- 
withstanding leaves  on  incineration  an  ash  containing 
an  alkaline  carbonate,  thus  proving  that  the  mass  con- 
tained an  organic  acid,  partly  free,  partly  combined 
with  alkali.  If  the  alcoholic  solution  be  mixed  with  a 
solution  of  tartaric  acid  in  alcohol,  potash,  soda,  and 
lime  are  deposited  in  the  form  of  tartrates,  and  there 

*  Handbuch,  Vol.  IX.  p.  573. 


24  LACTIC    ACID    TILL    LATELY 

remains  in  the  alcoholic  solution,  along  with  tartaric 
and  hydrochloric  acids,  a  combustible  acid  dissolved. 
The  solution  is  digested  with  finely-divided  carbonate 
t  of  lead,  till  lead  is  detected  in  the  liquid  ;  it  is  then 

evaporated,  the  lead  precipitated  by  hydrosulphuric 
acid,  the  acid  liquid  boiled  \vith  animal  charcoal 
and  evaporated.  It  leaves  a  colorless,  very  acid  syrup, 
possessing  all  the  characters  of  lactic  acid,  but  still  re- 
taining a  portion  of  extractive  matter  mixed  with  it." 

This  is  essentially  the  amount  of  all  that  is  known 
in  regard  to  the  nature  of  the  free  acid  present  in  the 
muscles. 

In  his  researches  on  urine  and  on  milk,  Berzelius, 
by  employing  a  similar  process,  obtained  also  strongly 
acid  extractive  substances,  the  properties  and  chemical 
relations  of  which  he  explained  by  the  presence  of 
lactic  acid. 

is  lactic  acid  Whether  these  statements  can  at  the  present  time  be 
regarded  as  proofs  of  the  existence  of  lactic  acid,  that 
is,  of  the  acid  now  called  by  that  name,  will  be  best 
seen  from  the  opinions  which  Berzelius  entertained 
concerning  the  nature  of  lactic  acid,  both  at  the  time 
when  his  researches  were  made  (1807),  and  subse- 
quently (1823  and  1828). 

Earlier  and         On  the   occasion  of  his  report  on  Daniell's  lampic 
Berzelius  as  acid,  Berzelius  observes,*  — "  These  researches  render 

to  the  nature  .A  ,        ,        .  .  ,         ,  .    , 

of  lactic  acid  it  very  probable  that  the  lactic  acid,  which  occurs  so 
frequently  in  the  animal  kingdom,  and  which  I  have 
endeavoured  to  prove  in  a  former  work  to  be  differ- 
ent from  acetic  acid,  is  likewise   nothing  more  than 
in  1807,        a  similar  combination  of  acetic  acid  with  a  peculiar 
1823,  animal  substance,  which  accompanies  it  in  its  salts,  is 

the  cause  of  the  differences  between  these  salts  and 

*  Jahresbericht,  Jahrgang  II.  p.  72. 


BUT    IMPERFECTLY    KNOWN.  25 

the  acetates,  and  moreover  prevents  the  volatilization  of 
the  acid,  as  long  as  the  foreign  matter  is  not  destroyed. 
A  further  inducement  to  adopt  this  opinion  is  derived 
from  the  circumstance,  that  concentrated  lactic  acid, 
when  neutralized  with  caustic  ammonia  and  heated, 
yields  distinctly  vapors  of  acetate  of  ammonia,  becom- 
ing acid  at  the  same  time." 

In  the  seventh  yearly  volume  of  his  Jahresbericht,  182*. 
^Berzelius  again  observes,  in  considering  Tiedemann  and 
Gmelin's  important  researches  on  digestion,  on  the  oc- 
casion of  their  mentioning  acetate  of  potash  as  an  in- 
gredient of  saliva  (p.  200),  — "They"  (Tiedemann 
and  Gmelin)  "  assume,  on  the  authority  of  Fourcroy 
and  Vauquelin,  as  well  as  of  their  own  experiments, 
and,  as  they  say,  of  mine  also,  that  lactic  acid  is  only 
acetic  acid,  rendered  impure  by  the  presence  of  an  an- 
imal matter.  I  have  certainly  made  experiments  with 
the  purpose  of  resolving  lactic  acid  into  acetic  acid  and 
a  foreign  substance  ;  but  I  am  not  aware  that  I  have 
ever  succeeded  in  doing  so  ;  and  as  long  as  we  cannot 
obtain  acetic  acid  from  it  without  destructive  distillation, 
or  as  long  as  lactic  acid  cannot  be  formed  from  acetic 
acid  and  an  animal  substance,  so  long  it  is  best  to  retain 
the  name  of  lactic  acid  ;  for  if  lactic  acid  be  a  chemi- 
cal compound  of  acetic  acid  with  an  animal  substance, 
which  enters  into  the  composition  of  the  salts,  and  de- 
prives the  acetic  acid  of  its  volatility,  it  would  be  as  in- 
accurate to  call  these  salts  acetates,  as  to  call  the  sul- 
phovinates  or  nitroleucates  sulphates  or  nitrates." 

In  his  last  investigation  on  this  subject,*  Berzelius  de-  and  1832. 
scribes  some  experiments,  from  which  it  might  be  con- 
cluded that  lactic  acid  contains  no  acetic  acid,  and  he 
terminates  his  researches  with  the  following  words  :  — 

*  Annalen  der  Pharmacie,  Vol.  I.  p.  1.     1832. 
3 


26  ACID    OF    THE    GASTRIC    JUICE. 

"  Future  investigations  must  be  chiefly  directed  to  as- 
certain, whether  that  which  has  been  called  lactic  acid 
be  a  mixture  of  two  acids,  which  resemble  each  other, 
but  yet  yield  different  salts." 
The  true  na-       From  these  passages  it  is  evident,  that,  at  the  time 

ture  of  lactic       ,  .          .          .  .  .  . 

acid  only  as-  when  chemists  began  to  reckon  lactic  acid  among  the 

certained  of     .  ,.  „    ,       „    .  ,      ^   ,  ,          , 

late  years.      ingredients  of  the  fluid  of  the  muscles,  the  properties  of 
the  acid  now  known  by  that  name  were  almost  entirely 
unknown  ;  so  much  so,  that  the  acid  discovered  by  Bra- 
connot,  which  is  formed  in  rice-water  and  in  the  juice  of 
beet-root,  was  considered  as  a  peculiar  acid  till  L.  Gme- 
lin  proved  it  to  be  identical  with  the  acid  of  sour  milk, 
and  C.  Mitscherlich  described  his  method  of  obtaining 
lactic  acid  from  sour  milk  in  a  state  of  purity. 
The  former         It  is  plain  that  the  assumption  of  the  existence  of  lac- 
the  presence  tic  acid   in  the  animal  body,  founded,  forty  years  ago, 
in  the  body    on  grounds  so  uncertain  and  variable,  could  no  longer 
iufficientf*    De  admitted  in  our  day,  more  particularly  as  no  chem- 
ist, after  Berzelius,  has  occupied  himself  with  a  more 
exact  study  of  the  subject,  or  has  attempted  to  prove 
that  the  acid  of  the  muscles  is  identical  with  that  of  sour 
milk.     This  identity,  or  indeed  the  presence  of  a  non- 
nitrogenized  organic  acid  as  an  ingredient  of  the  living 
body,  was  rendered  still  more  doubtful  and  improbable, 

especially  as   when  the  accurate  investigation  of  urine,  in  which  lac- 
it  has  been 

shown  not      tic  acid  was  said  to  be  present,  had  proved  the  absence 

to  exist  in  .     . 

urine.  of    it  in  that  fluid. 

What  is  the  I  regarded  -the  determination  of  the  nature  of  the 
gastric  juice?  acid  diffused  through  the  chief  mass  of  the  body  as 
the  more  important,  that  this  alone  could  give  us  an  ex- 
planation of  the  nature  and  origin  of  the  acid  which 
takes  a  share  in  the  digestive  process.  The  acid  of  the 
gastric  juice  is  not  formed  during  digestion  from  the  in- 
gredients of  the  food,  which  in  themselves  are  not  acid, 
but  is  secreted  from  the  lining  membrane  of  the  stom- 


KREATINE    DISCOVERED.  —  ITS    PROPERTIES.  27 

ach,  even  in  the  fasting  state.  If  this  acid  were  an  in- 
gredient of  the  blood,  then  it  must  admit  of  being  de- 
tected in  the  blood  or  in  some  other  part  of  the  body. 

Several  French  chemists,  resting  their  conclusions  Supposed  by 

some,  on 

on  qualitative  researches,  have  indeed  stated  that  the  verydefec- 
•  1^1  ......        -11  •         l*ve  evi~ 

acid  of  the  gastric  juice  is  lactic  acid  ;  but  the  reactions,  dence,  to  be 

.  .    ,  111'  p  i  -j     lactic  acid. 

which  were  held  to  prove  the  presence  of  lactic  acid, 
either  do  not  belong  to  that  acid,*  or  are  such  as  lactic 
acid  possesses  in  common  with  other  acids,  particularly 
with  phosphoric  acid,  which  is  never  absent  in  animal 
fluids. 

In  1835,  Chevreul  described,  as  an  ingredient  of  the  Kreatine  dis- 

i  i       ,     •!•          n      i         •  i  i      covered  by 

liquid  obtained  by  boiling  flesh  with  water,  a  new  sub-  Chevreul. 
stance,  under  the  name  of  Kreatine  (from  Kpeas,  flesh), 
which  was  distinguished  by  its  properties  from  all  known 
compounds.  He  obtained  it  in  very  small  quantity  by 
acting  with  alcohol  on  the  residue  obtained  by  evapo- 
rating the  soup  in  vacuo. 

The  properties  of  kreatine,  as  observed  by  this  dis-  His  account 

.  of  its  proper- 

tinguished  chemist,  are  as  follows  :  —  "  Kreatine  is  dis-  ties, 
tinguished  by  the  transparency  of  its  crystals,  which  are 
right-angled  prisms  of  mother-of-pearl  lustre  ;  it  is  heav- 
ier than  nitric  acid  of  sp.  g.  1.34,  and  lighter  than  sul- 
phuric acid  of  sp.  g.  1.84.  It  has  no  action  on  vegeta- 
ble colors ;  its  solution  in  water  is  not  precipitated  by 
chloride  of  barium,  by  oxalate  of  ammonia,  nitrate  of 
silver,  sulphate  of  copper,  protosulphate  of  iron,  suba- 
cetate  of  lead,  or  bichloride  of  platinum.  1,000  parts 
of  water  at  15°  C.  (64°  F.)  dissolve  12.04  parts  of  kre- 
atine ;  alcohol  of  sp.  g.  0.804  dissolves  about  ^V^h  °f 
its  weight.  Its  solution  in  nitric  acid,  when  warmed, 
gives  off  nitrous  acid,  and  leaves,  on  evaporation,  a  resi- 
due, which  gives  a  precipitate  with  chloride  of  platinum, 

*  See  Annalen  der  Chemie  und  Pharmacie,  Vol.  LXI.  p.  216. 


28 


PROPERTIES    OF    KREATINE. 


and  deposits  small  granular  crystals.  Kreatine  dis- 
solves in  hydrochloric  acid :  the  solution  gives,  on 
evaporation,  colorless  dendritic  crystals,  which  do  not 
precipitate  bichloride  of  platinum. 

u  In  its  aqueous  solution,  kreatine  is  spontaneously 
although  slowly  decomposed,  there  is  observed  a  dis- 
tinct odor  of  ammonia  along  with  a  heavy,  mawkish 
smell ;  the  liquid  loses  its  transparency. 

"  When  heated  in  a  small  tube,  kreatine  decrepitates, 
gives  off  water,  becomes  opaque  and  dull,  then  melts 
without  becoming  colored,  and  is  finally  decomposed, 
ammonia  being  disengaged,  along  with  a  smell  of  hy- 
drocyanic acid  and  phosphorus.  There  is  condensed 
in  the  upper  part  of  the  tube  a  yellow  vapor,  partly  in 
the  liquid  state,  partly  in  the  form  of  crystals.  The 
carbonaceous  residue  is  trifling,  and  leaves,  on  incinera- 
tion, a  mere  trace  of  ashes,  which  contain  no  chloride 
of  sodium. 

"  Kreatine  contains  water  of  crystallization,  which  is 
expelled  by  a  heat  of  212°  ;  its  ultimate  elements  are 
carbon,  hydrogen,  nitrogen,  and  oxygen,  in  proportions 
not  yet  ascertained."  (Journal  de  Pharmacie,  Vol.  XXI. 
p.  236.) 

opinion  of         Chevreul  compares  this  substance  with  asparagine. 

10  its  nature,  and  shows  that  it  cannot  be  confounded  with  that  sub- 
stance. He  adds,  that  kreatine,  when  acted  on  by  ba- 
ryta, yields  an  acid  very  different  from  aspartic  acid. 
"  Perhaps,"  he  says,  "  it  is  an  ammoniacal  salt,  formed 
by  the  combination  of  ammonia  with  an  organic  acid." 

Berzeiius  en-       After  Chevreul  had  published  his  observations  on  the 

deavours  to  .  11- 

obtain  it.  occurrence  of  kreatine,  several  chemists  endeavoured 
again  to  obtain  this  substance.  Berzeiius  observes  on 
this  subject,  in  his  "  Handbuch,"  that  "  After  the  dis- 
covery of  Chevreul  became  known,  I  tried  in  vain  to 

His  opinion,    prepare   this   substance  from  raw  beef.     Meantime    I 


ATTEMPTS    TO    OBTAIN    IT.  29 

have  had  an  opportunity  of  seeing  kreatine  in  the  pos- 
session of  that  distinguished  chemist.  It  would  appear, 
therefore,  rather  to  be  an  accidental  ingredient,  the 
presence  of  which  depends  on  peculiar  circumstances 
in  the  feeding  of  the  cattle,  and  which  therefore  is 
sometimes  present  and  at  other  times  absent.  If,  ac- 
cordingly, it  should  be  found  in  the  liquid  in  which  beef 
has  been  boiled,  it  would  evidently  be  the  product  of  a 

metamorphosis."     Wohler  observes,  in  a  note  on  this  wshier  ob- 
tains it.    It 
passage,  —  "I  have  obtained  this  substance  from  the  isnotaiian- 

soup  of  8  Ibs.  of  beef,  in  yellowish  crystals.  It  is  not 
allantoine,  as  I  suspected  it  might  be." 

Schlossberger,  in  his  examination  of  the  muscles  of  Schiossber- 

ger  finds  it  in 

the  alligator,*  says,  —  "  The  aqueous  extract  of  the  the  flesh  of 
flesh,  heated  to  coagulate  the  albumen,  filtered,  and 
evaporated  in  the  water-bath,  yielded  a  brownish-yellow 
syrup,  pretty  strongly  acid,  with  an  odor  of  roast  meat, 
such  as  is  understood  under  the  term  Osmazome,  as  ob- 
tained from  ordinary  flesh.  Hot  alcohol  dissolved  a 
considerable  part  with  a  yellow  color,  and  deposited,  on 
cooling,  small  cubical  yellowish  crystals,  which  may  be 
washed  with  water,  or  better  with  alcohol.  Thus  puri- 
fied, they  had  all  the  characters  of  Chevreul's  kreatine. 
When  heated,  they  become  white  and  opaque,  then 
melt,  giving  out  a  yellow  vapor  and  an  ammoniacal 
empyreumatic  odor,  leaving  a  coal,  which,  after  long 
ignition,  leaves  a  mere  trace  of  ashes.  Heated  with 
nitric  acid  on  the  platinum  spatula,  they  caused,  for  an 
instant,  on  the  addition  of  ammonia,  a  rich  yellow  color, 
soon  passing  into  brown.  They  dissolved  in  strong  ni- 
tric acid  with  the  evolution  of  yellow  vapors,  and  the 
solution,  when  evaporated,  left  a  white  residue.  The 
aqueous  solution  of  the  crystals  is  not  precipitated  by 

*  Annalen  der  Chemie  und  Pharmacie,  Vol.  XLIX.  p.  343. 
3* 


30 


KREATINE  IN  THE  JUICE  OF  FLESH. 


Schiossber- 


Results  of 


nitrate  of  silver,  subacetate  of  lead,  or  salts  of  baryta. 
Unfortunately  the  quantity  in  my  possession  was  not 
sufficient  for  an  elementary  analysis,  since  from  several 
pounds  of  flesh  I  only  obtained  0.15  gramme  (2.3 
grains).  At  all  events,"  continues  Dr.  Schlossberger. 
u  it  is  desirable  to  recommence  the  search  for  this  sin- 
gular substance,  which  Chevreul  discovered  in  the  soup 
of  the  Dutch  Company,  but  which  Berzelius  and  Simon 
could  not  obtain.  I  myself  was  also  unable  to  detect  it 
in  my  numerous  analyses  of  flesh  in  1838,  although  I 
expressly  sought  for  it.  Wohler  has  obtained  a  small 
quantity  from  ox-flesh,  and  has  determined  that  it  is  not 
allantoine.  It  would  appear,  therefore,  either  not  usu- 
ally  to  occur  in  the  substance  of  the  muscles,  or  to  oc- 
cur in  so  small  a  quantity  that  it  cannot  be  detected. 
However  this  may  be,  the  detection  of  this  substance, 
so  well  characterized  by  its  tendency  to  crystallize  and 
its  whole  chemical  character,  in  the  flesh  of  animals  so 
widely  separated  as  the  ox  and  the  crocodile,  must  be 
regarded  as  a  fact  worthy  of  attention." 

This  is  the  essential  part  of  all  that  is  known  from 
"  previous  researches  in  regard  to  lactic  acid  and  krea- 
tine  as  ingredients  of  flesh.  With  respect  to  the  other 
substances  which  are  spoken  of  in  chemical  works  as 
ingredients  of  flesh,  I  believe  I  need  make  no  further 
quotations,  since  their  intimate  chemical  relations  are 
entirely  unknown,  and  they  offer  no  remarkable  pecu- 
liarities beyond  the  facts  that  they  are  precipitated  by 
acetate  and  subacetate  of  lead,  by  corrosive  sublimate, 
tannic  acid,  or  chloride  of  tin. 

In  the  early  part  of  my  investigation  I  succeeded. 
after  many  fruitless  attempts,  in  obtaining  a  small  quan- 
tity of  kreatine  from  the  juice  of  the  flesh  of  fowls,  and 
the  study  of  its  chemical  relations  soon  showed  that  this 
substance,  during  the  evaporation  of  the  fluid,  loses  its 


METHOD  OF  OBTAINING  KREATINE.        31 

power  of  crystallizing,  in  consequence  of  a  change 
which  it  undergoes  under  the  influence  of  the  free 
acid  present  in  the  soluticfa,  and  that  in  this  way  its  pu- 
rification arid  preparation  are  rendered  much  more  diffi- 
cult. The  separation  of  the  non-nitrogenized  acid, 
which  I  soon  found  to  be  present  in  the  juice  of  flesh, 
was  at  first  attended  with  no  small  difficulties,  and  ulti- 
mately it  is  only  the  more  exact  acquaintance  with  the  and  in  devis- 

„    .  •.          .  ,         in=  simple 

other  substances  occurring  in  this  fluid  which  has  led  methods  of 

Ai  •        i  ,1      i          />  •  ,•         obtaining  the 

to   the   simple    methods    of  preparing  and   separating  constituents 
them,  to  be  described  in    the  following    pages  in  the  ° 
order   in  which   they  present   themselves   to   the   ob- 
server. 

When  the  finely  minced  flesh  of  newly-killed   ani-  Flesh  ex- 

,  .  .  traded  by 

mals  is  extracted  by  water,  there  is  obtained  a  red  or  water. 
reddish-colored  fluid,  having  the  taste  which  is  peculiar 
to  the  blood  of  different  classes  of  animals.  If  this 
fluid  be  heated  in  the  water-bath,  the  albumen,  as  Ber- 
zelius  has  observed,  coagulates  first,  and  the  liquid  re- 
tains its  red  color.  The  albumen  at  first  separates  as  Albumen  and 

coloring  mat- 

a  nearly  colorless  coagulum,  which  afterwards  collects  tcrcoaguiat- 

.      .  .     ed  by  heat. 

in  denser  flocculent  masses,  and  the  coloring  matter  is 
only  separated  at  a  considerably  higher  temperature. 
It  is  easy  to  observe  the  point  at  which  the  albumen  has 
been  entirely  coagulated,  while  the  red  coloring  matter 
still  remains  in  solution.  It  is  now  only  necessary  to 
bring  the  liquid  into  actual  ebullition  in  a  silver  or  por- 
celain vessel,  in  order  to  separate  the  whole  of  the  col- 
oring matter  in  the  coagulated  state,  and  we  thus  obtain  The  filtered 

«        liquid  is  acid. 

a  liquid  easily  filtered,  which  reddens  litmus  powerful- 
ly. The  coagulated  albumen,  together  with  the  undis- 
solved  fibrine  and  cellular  tissue,  has  an  acid  reaction, 
which  cannot  be  removed  by  washing  with  water.  The 
insoluble  residue  of  the  flesh  (fibrine,  cellular  tissue, 
&c.),  when  boiled  with  water,  becomes  opaque,  milk- 


32 


METHOD    OF    EXTRACTING 


A  good 
press  is  in- 
dispensable. 


Small  propor- 
tion of  solu- 
ble matter  in 
flesh. 


8  or  10  Ibs. 
of  flesh 
should  be 
used. 


Best  mode 
of  extraction. 


white,  of  horny  hardness,  and  the  water  acquires  by 
dissolving  gelatine  the  property  of  gelatinizing  on  cool- 
ing, when  sufficiently  concentVated. 

If  we  desire  to  obtain  the  soluble  constituents  of 
the  muscular  substance  without  great  loss,  and  without 
using  inconveniently  large  quantities  of  water,  a  good 
press  is  indispensable.  We  can,  it  is  true,  by  the  pro- 
cess I  am  about  to  describe,  obtain  with  ease  each 
of  the  substances  mentioned,  but  to  this  end  it  is  not 
advisable  to  operate  on  less  than  from  8  to  10  Ibs.  of 
flesh.  It  is  only  necessary  to  reflect  that  flesh  con- 
tains from  76  to  79  per  cent,  of  water,  and  from  2  to 
3  per  cent,  of  soluble  albumen,  and  that  after  extrac- 
tion with  water  there  are  left  from  17  to  18  per  cent, 
of  fibrine  and  other  insoluble  matters,  in  order  to  per- 
ceive that  even  when  we  employ  10  Ibs.  and  upwards 
of  flesh  we  are  still  operating  on  comparatively  small 
quantities  of  the  soluble  constituents.  (On  the  aver- 
age, the  soluble  matter  of  10  Ibs.  of  flesh,  after  the 
coagulation  of  the  albumen  and  coloring  matter,  does 
not  exceed  4  oz.,  and  of  this  a  very  considerable 
proportion  consists  of  inorganic  salts,  the  phosphates 
being  particularly  abundant,  while  the  remainder  is 
formed  of  not  less  than  five  organic  compounds.) 

Supposing  that  10  Ibs.  of  flesh  are  to  be  operated 
upon,  the  half  of  this  quantity  is  taken,  and  covered 
with  5  Ibs.  of  water.  The  mixture  is  carefully  knead- 
ed with  the  hands,  and  is  then  pressed  as  completely 
;is  possible  in  a  bag  of  coarse  linen.  The  pressed  resi- 
due is  a  second  time  carefully  kneaded  with  5  Ibs.  of 
water,  and  again  pressed.  The  fluid  of  the  first  press- 
ing is  set  aside  for  further  operations,  that  of  the  sec- 
ond being  used  for  the  first  extraction  of  the  second 
half  of  the  flesh.  In  like  manner  the  residue  of  the 
first  half  is  a  third  time  treated  with  5  Ibs.  of  water. 


THE    CONSTITUENTS    OF    FLESH.  33 

and  the  expressed  fluid  serves  for  the  second  extrac- 
tion of  the  second  half,  which  is  finally  extracted  a 
third  time  with  pure  water,  in  which  it  is  allowed  to 
soften,  and  again  pressed  out. 

The  united  liquids  are  passed  through  a  clean  cloth  Coagulation 

of  the  albu- 

to  separate  any  fragments  of  muscular  fibre,  and  then  men  and  coi- 

oring  matter. 

introduced  into  a  large  glass  globe,  which  is  placed 
in  a  pan  of  water,  the  latter  being  gradually  heated 
to  the  boiling  point,  and  kept  at  this  temperature  till 
the  liquid  has  lost  its  color,  and  the  whole  of  the  albu- 
min and  coloring  matter  have  separated  in  a  coagu- 
lum.  When  a  portion,  heated  to  boiling  in  a  test  tube, 
remains  clear,  and  deposits  no  flocculi,  this  operation 
is  completed. 

In  many  kinds  of  flesh,  it  is  necessary,  in  order  to 
separate  the  last  traces  of  coloring  matter  after  the 
coagulation  of  the  albumen,  to  remove  the  liquid  from 
the  globe,  and  bring  it  into  actual  ebullition  in  a  silver 
or  porcelain  vessel,  which  is  so  much  the  more  easily 
done  that  the  adhesion  of  the  coagulum  to  the  bottom 
of  the  vessel,  where  it  would  be  singed  or  burnt,  is  no 
longer  to  be  dreaded.  It  is  moreover  advisable  to  re-  All  visible  fat 

should  be  re- 
move all  visible  fat  as  completely  as  possible  from  the  moved. 

flesh,  or  to  select  the  flesh  of  lean  animals,  because 
the  fat  very  much  impedes  both  the  extraction  of  the 
flesh  with  water  and  the  pressing  of  the  mass.  When 
fat  flesh  is  used,  the  cloths  or  bags  in  which  it  is  pressed 
become  quickly  useless,  their  pores  being  clogged  with 
fat. 

The  liquid,  after  the  coagulation  of  the  albumen  and  Characters  of 

the  liquid  fil- 

colonng  matter,  is  strained  through  a  cloth,  the  coagu-  tered  from 

6        the  coaau- 

lum  pressed,  and  the  united  liquids  filtered.  him. 

The  color  of  the  filtered  liquid  varies  with  the  kind 
of  flesh.  That  from  flesh  very  full  of  blood,  as  is 
that  of  the  ox,  roe-deer,  hare,  and  fox,  has  a  reddish 


34          EXTRACTION  OF  THE  SOLUBLE 

color ;  while  that  from  veal  and  fowl,  as  well  as  that 
from  fish,  is  hardly  colored. 

For  the  preparation  of  kreatine,  the  flesh  of  wild 
animals  and  of  common  fowls  is  the  best  adapted. 
The  liquid  obtained  from  these  kinds  of  flesh  is,  when 
filtered,  clear  and  limpid ;  that  of  the  horse  and  of 
fish  is  always  turbid  ;  the  taste  of  all  is  nearly  the 
same,  and  the  fluid  from  the  flesh  of  the  fox  is  in 
this  respect  not  distinguishable  from  that  derived  from 
lean  beef.  The  fluid  from  the  flesh  of  the  marten 
possesses  a  distinct  musky  smell,  which  becomes  more 
decided  when  it  is  heated  and  evaporated. 
The  liquid  is  All  the  different  fluids  obtained  by  the  above  pro- 

always  acid.  ,  .  ,  .  ,  .    , 

cess  have  an  acid  reaction,  which  appears  to  me  the 
more  worthy  of  notice,  that,  in  the  case  of  the  ox, 
sheep,  and  game,  it  can  only  be  obtained  mixed  with 
a  proportionally  large  quantity  of  blood ;  and  yet  the 
alkali  contained  in  the  blood,  on  which  its  alkaline 
reaction  depends,  is  yet  not  sufficient  to  neutralize  the 
free  acid  present  in  the  fluid  of  the  flesh.  Indeed,  I 
believe  that  in  most  animals,  if  we  suppose  the  whole 
mass  of  blood  in  the  vessels  to  be  mixed  with  the 
and  does  not  whole  fluid  of  the  muscles,  the  mixture  would  retain. 

become  neu- 

trai  when  the  not  a    neutral    or  alkaline,  but  an  acid    reaction.     In 

blood  is  add-  . 

ed  to  it.         the  hare,  the  amount  of  whose  blood  is  proportionally 

small,  this  is  certainly  the  case. 

The  acid  li-         If  the  clear  liquid,  as  obtained  by  filtration,  be  con- 
oration  be-ap   centra  ted  over  the  open  fire,  even  without  being  heated 
an?ySieidsWll>  to  the   boiling  point,   it  becomes    gradually  darker   in 
als'   color,  and  at  last  leaves  a  dark  brown   syrup,  with  a 
smell    of  roast   meat,  in  which    traces  of  kreatine    in 
crystals  only  appear  after  it  has  stood  for  a  long  time. 
The  brown  color  is  in  part  caused  by  the  formation 
of  a  deposit  of  dissolved  matter,  which  attaches  itself 
to  the  bottom  of  the  vessel,  and,  in  consequence  of  the 


CONSTITUENTS    OF    FLESH.  35 

higher  temperature  to  which  it  is  there  exposed,  passes 
into  a  dark  soluble  substance ;  but  even  when  this  de- 
posit is  avoided,  as,  for  example,  when  the  evaporation 
is  conducted  in  the  water-bath,  the  dark  color  infalli- 
bly appears.     The  chief  cause  of  it,  besides  the  tern-  The  acid 
perature,  is  the    presence  in    the   liquid  of  free  acid,  moved6  r 
which  must  be  removed  before  evaporation. 

To  this  end  there  is  added  to  the  liquid  a  concen-  by  the  addi- 
trated  aqueous  solution  of  baryta,  as  long  as  it  pro-  ryta. 
duces  a  white  precipitate.     After  a  certain  quantity  of 
baryta  has  been  added,  the  liquid  becomes  neutral  or 
even  alkaline ;  but  this  must  not  prevent  us  from  adding 
it  as  long  as  it  causes  the  slightest  turbidity  in  a  fil- 
tered portion  of  the  liquid. 

The    precipitate  thus  formed  consists  of  phosphate  Phosphates 
of  baryta,  and  phosphate  of  magnesia,  and  contains  tated.reC1 
none  of  the    double   phosphate  of  ammonia  and  mag- 
nesia ;  nor  is  ammonia  disengaged  by  the  addition  of 
baryta.     In  one    operation   alone,  out   of  many,  was  No  ammonia 

,.     .  •  P  -11  *s  disen- 

a  distinct  separation  of  ammonia  observed.  gaged, 

The    precipitate    from  the    liquid  derived    from  the  and  no  sul- 
phates are 
flesh  of  fowls   dissolves  in  diluted   hydrochloric    acid  found  in  the 

_    .        .  ....          ,    .  precipitate. 

without  residue ;  and  in  those  cases  in  which  sulphate 
of  baryta  remains  undissolved,  its  quantity,  compared 
with  that  of  the  flesh,  is  so  trifling,  that  we  may  as- 
cribe with  perfect  certainty  the  sulphuric  acid  thus  in- 
dicated to  the  mixture  of  a  little  blood. 

After  the  separation  of  the  precipitate,  which  con-  The  filtered 
tains  the  whole  phosphoric  acid  of  the  fluid  of  flesh,  be  gently 
the  filtered  liquid  is  divided  into  flat  porcelain  dishes,  ev 
and  concentrated  in  the  water-bath  or  sand-bath,  taking 
care   that   it   never   boils.     If  the  upper   edge  of  the 
evaporating  dish  be  allowed  to  become  hotter  than  the 
liquid,  a  portion  is  always  dried  up  on  this  part,  form- 
ing a  dark  brown  ring,  which,  on  the  addition  of  fresh 


36  SEPARATION  OF  KREATINE. 

liquid,  dissolves  in  it  without  perceptibly  coloring  it ; 
but  in  this  case  the  color  comes  out  when  the  liquid 
is  concentrated.  When  the  liquid  from  fowl's  flesh, 
after  the  action  of  baryta,  is  evaporated,  it  continues 
perfectly  clear,  only  if  an  excess  of  baryta  has  been 
added,  a  film  of  carbonate  of  baryta  forms  on  the 
surface. 

In  the  evaporation  of  the  same  fluid  from  beef,  there 

is  formed,  when  it  has  acquired  a  syrupy  consistence, 

a  mucilaginous  skin  on  the  surface,  which,  when  di- 

A  skin          vided  in   water,  swells  up  without  dissolving.     In  the 

Scales     case  of  the  flesh  of  the    calf  and  of  the  horse,   these 

o"atio?\evap"   skins  or  membranes  succeed  each  other  continually ; 

they  may  be    removed  as  coherent    membranes,  and 

they  must  be  taken  away  as  often  as  their  formation 

is  repeated. 

The  concen-        When  the  fluid  has  been  reduced  to  about  510  of  its 
deapa?itsiquld   original  volume,  and  has  acquired  a  thickish  consist- 
erysta™ m     ence,  it  is  placed  in  a  moderately  warm  situation,  and 
left   to  evaporate  slowly.     Very  soon   small,  distinct, 
short,  colorless  needles  appear  on  the  surface,  which 
increase  on  standing,  and  on  cooling,  so  that  the  walls 
of  the  vessel  are  gradually  covered  with  them. 
These  crystals  are  kreatine. 

The  process  thus  described  applies  to  all  the  differ- 
ent kinds  of  flesh  above  mentioned,  except  that  of  fish, 
for  which  a  modification  of  it  is  required. 

Modification  The  ^esn  °^  fis^es?  when  finely  minced,  cannot  be 
"LshforPfi°3h.  Pressed ;  it  swells  up  with  water  to  a  mucilaginous 
mass,  which  clogs  up  the  pores  of  the  cloth.  We 
have,  therefore,  no  choice  but  to  mix  it  with  twice  as 
much  water  as  above  recommended,  to  throw  the  mix- 
ture on  a  funnel,  and  to  displace  the  fluids  by  re- 
peated affusion  of  small  quantities  of  water.  The  in- 
fusion is  colorless,  slightly  opalescent,  has  an  acid  re- 


AMOUNT    OF    KREATINE    IN    FLESH.  37 

action  and  a  very  marked  taste  and  smell  of  fish. 
When  heated,  it  yields  a  perfectly  white,  soft  coagu- 
lum,  and  after  the  addition  of  baryta,  when  evap- 
orated and  allowed  to  cool,  yields  a  colorless  jelly, 
in  which,  when  allowed  to  rest,  very  distinct  and 
regular  crystals  of  kreatirie  form  after  twenty-four 
hours. 

The   quantity   of  kreatine   obtained    from    different  Proportion  of 
kinds  of  flesh  is  very  unequal.     Of  all  kinds,  the  flesh  different "' 
of  fowl    and   that   of   the    marten   contain   the    most,  flesh?  ° 
then  that  of  the  horse,  the  fox,  the  roe-deer,  the  red 
deer  and  hare,  the  ox,  pig,  calf,  and  finally  that  of 
fishes. 

The  variation  in  the  amount  of  kreatine  is  striking,  it  is  greater 

„    ,  °     in  wild  than 

even  in  animals  01  the    same   class.      Ihe  flesh  of  a  in  confined 
fox,  fed  on  flesh  for  two  hundred  days  in  the  anatomi- 
cal rooms  at  Giessen,  did  not  yield  so  much  as  the 
tenth  part  of  the  quantity  of  kreatine   obtained  from 
foxes  killed  in  the  chase. 

The  amount  of  kreatine  in  the  muscles  of  an  ani-  its  amount 
mal  stands  in  an  obvious  relation  to  that  of  fat,  or  to  tioTtAhat" 
the  causes  which  determine  the  deposition  of  fat.    From  °f 
fat  flesh  there  are  often  obtained  mere  traces  of  krea- 
tine, and  always  much  less  than  from  lean  flesh,  for 
the  same  amount  of  muscular  fibre.     The  fox  above 
mentioned,  which   had   been   fed,  yielded  more   than 
1  Ib.  of  fat  from  the  omentum,  while  in  foxes  hunted 
or  shot  hardly  any  fat  was  visible. 

From  100  Ibs.  (Hessian)  of  the  flesh  of  an  old,  lean  Actual 

v  m       '  amount  of 

horse,  there  were  obtained  nearly  36  grammes    (555  kreatine  ob- 
grains)  of  kreatine.     116  lean  fowls  yielded  about  72  the  author, 
grammes  (1,110  grains);  and  86  Ibs.  of  beef  30  gram- 
mes (463  grains). 

The  weight  of  the  flesh  of  a  fowl  was,  on  an  aver- 
age, 203  grammes  (3,134  grains,  or  about  7  oz.  avoir- 
4 


38  AMOUNT    OF    KREATINE    IN    FLESH. 

dupois) ;  that  of  wild  foxes  weighed  from  2  to  2-|-  Ibs. 
(Hessian).* 

Kreatine  I  have  found,  as  already  stated,  kreatine  in  the  flesh 

thenhigher  of  the  ox,  sheep,  pig,  calf,  roe-deer,  hare,  marten, 
aSai30f  ^ox?  red  deer,  common  fowl,  and  fish ;  and  as  it  can- 
not be  doubted  that  the  crystals  obtained  by  Schloss- 
berger  from  the  flesh  of  the  alligator  were  also  krea- 
tine, it  may  fairly  be  concluded  that  this  substance 
is  an  ingredient  of  the  muscles  of  all  the  higher  class- 
es of  animals. 

u  is  not  to  be      I  have  not  beeen  able,  by  the  same  process,  to  de- 
toain, 'liver,    tect  kreatine  in  the  substance  of  the  brain,  of  the  liver, 

or  kidneys,  *»    i       i  •  i  i          ••  ,    •         i         i 

but  the  heart  or  of  the  kidneys ;  but  it  is  present  in  abundant  quan- 

contains  it.      , •  ,       •       ,1        i  />  , i  ±1     ±   ^  • 

tity  m  the   heart  of  the  ox,  so  that  this  organ  is  es- 
pecially adapted  for  its  preparation.     The  study  of  the 
substance  of  the   brain  and  liver  presented  a  number 
of  peculiarities,  which  promise    valuable  results  on  a 
closer  investigation.    Thus,  for  example,  when  the  sub- 
Peculiarities   stance  of  the  brain  is  rubbed  with  barytic  water  to  a 
vestigation     thin  emulsion,  passed  through  a   fine    hair-sieve,  and 

in  the  brain  ,  .     ...  , 

and  liver.       heated   to   boiling,    there  is   obtained  a  coagulum,  in 


*  Note  by  the  Editor.  —  The  figures  in  the  text,  when  re- 
duced to  1000  parts,  indicate  that 

1000  parts  of  the  flesh  of  Fowl  yielded  3.05  kreatine  (crude  ?) 
1000  "  the  Horse     "      0.72         « 

1000  "  the  Ox          "      0.697       " 

In  one  experiment  I  obtained  from  the  flesh  of  eight  fowls, 
weighing  hardly  3£  Ihs.,  78.75  grains  of  purified  kreatine,  or 
3.21  parts  from  1000.  A  second  experiment,  with  the  same 
quantity  of  flesh,  yielded  71  grains  of  pure  kreatine,  or  2.9  parts 
in  1000.  Not  having  been  provided  with  a  proper  press,  consid- 
erable loss  was  unavoidably  sustained  in  both  these  experiments, 
which  were  also  made  on  a  smaller  scale  than  is  recommended 
in  the  text.  The  average  of  the  two  agrees  exactly  with  the 
result  obtained  by  the  author,  namely,  from  fowl  3.05  parts  in 
1000.  —  W.  G. 


CHEMICAL    HISTORY    OF    KREATINE.  39 

which  is  contained  all  the  fat  of  the  brain,  and  a  clear 
yellowish  liquid,  which,  when  deprived  of  the  excess  of 
baryta  by  a  current  of  carbonic  acid  gas,  and  subse- 
quent boiling,  contains  two  salts  of  baryta,  one  «of 
which  is  soluble  in  alcohol.  Both  are  soluble  in  water, 
and  give  with  acids  a  white  flocculent  precipitate. 

Kreatine. 
The    crystals    of   kreatine,    obtained    as   above    de-  Purification 

•  i      i  ,  ,.  of  kreatine. 

scribed,  are  separated  from  the  mother  liquid  by  a 
filter,  washed  first  with  a  little  water,  then  with  alco- 
hol, and  dissolved  in  boiling  water.  If  the  solution 
should  be  colored,  some  animal  charcoal  (from  blood) 
is  added,  and  a  very  small  quantity  is  sufficient  to  give 
a  liquid  which,  when  filtered,  is  colorless  and  limpid, 
and  which,  on  cooling,  deposits  the  kreatine  in  perfect- 
ly pure  crystals. 

If  the  phosphoric  acid  has  not  been  entirely  removed 
by  means  of  baryta,  then  the  original  crystals  are  mixed 
with  phosphate  of  magnesia,  of  which  the  greater  part 
is  left  behind  on  recrystallization ;  but  a  small  portion  dis- 
solves and  is  deposited  along  with  the  crystals  of  kre- 
atine. To  remove  this  impurity,  the  filtered  solution  is 
boiled  with  a  little  hydrated  oxide  of  lead,  filtered,  and 
then  treated  with  a  little  animal  charcoal,  which  absorbs 
the  traces  of  oxide  of  lead  that  may  have  been  dissolved. 

The   crystals    of    kreatine   are    colorless,   perfectly  Description 
transparent,  and  of  the  highest  lustre  ;  they  belong  to  tais.  e  °rys 
the  klinorhombic  system,  and  form  groups,  the  charac- 
ter of  which  is  exactly  similar  to  that  of  sugar  of  lead. 
At  212°,  the  crystals  become  dull  and  opaque,  with  loss 
of  water. 

0.485  gramme  of  crystallized  kreatine  lost,  at  212°,  Analysis  of 

kreatine. 

0.059  gramme  of  water  =  12.16  per  cent. 

0.3582  gm.  of  crystallized  kreatine  lost,  at  212°, 
0.044  gm.  of  water  =  12.28  per  cent. 


40  ANALYSIS    OF    KREATINE. 

0.5835  gm.  of  crystallized  kreatine  lost,  at  212°, 
0.0705  gm.  of  water  =  12.08  per  cent. 

0.603  gm.  of  crystallized  kreatine  lost,  at  212°, 
0.0753  gm.  of  water  =  12.18  per  cent. 

Hence  100  parts  lost,  on  an  average,  at  212°,  12.17 
parts  of  water  of  crystallization. 

The  combustion  of  dried  as  well  as  of  crystallized 
kreatine  with  oxide  of  copper  yielded  a  gaseous  mix- 
ture, which  contained,  for  388  volumes  of  nitrogen, 
1,036  vol.  of  carbonic  acid.  Hence  kreatine  contains, 
for  8  vol.  of  carbonic  acid  or  8  eqs.  of  carbon,  3  vol. 
or  eqs.  of  nitrogen.* 

Further,  in  combustion  with  chromate  of  lead,  — 

0.5628  gm.  of  crystallized  creatine  yielded  0.6764  gm. 
of  carbonic  acid.  (The  water  was  lost  in  this  analysis.) 

0.5830  gm.  of  crystallized  kreatine  yielded  0.693 
gm.  of  carbonic  acid,  and  0.388  gm.  of  water. 

0.545  gm.  of  crystallized  kreatine  yielded  0.658  gm. 
of  carbonic  acid,  and  0.367  gm.  of  water. 

0.2884  gm.  of  crystallized  kreatine  yielded  1.300 
gm.  of  the  double  chloride  of  platinum  and  ammoni- 
um, =  28.32  per  cent,  of  nitrogen. 

These  analyses  yielded,  for  100  parts  of  kreatine  : 


I. 

II. 

III. 

Carbon 

32.77 

32.91 

32.4  It 

Nitrogen 
Hydrogen 
Oxygen 

.    23.32 
u 

(C 

28.32 
733 
31.44 

28.32 
739 
31.88 

100.00 

100.00 

*  The  2d  tube  gave  for  89  vol.  nitrogen  217  vol.  carbonic  acid. 
3d  "          64  "          156 

4th            "          78            "          219  " 

5th            "          77            "          224  " 

6th            «          80            "          220  « 

Total  "        388  "        1036 

t  In  combustion  with  chromate  of  lead,  it  is  well  known  that 


ANALYSIS    OF    KREATINE, 


41 


corresponding  to  the  formula, 

8  eq.  Carbon  ....  48  32.22               Formula. 

3  eq.  Nitrogen  ....  42  28.19 

11  eq.  Hydrogen  ....  11  7.38 

6  eq.  Oxygen  .         .         .         .  48  32.21 

Atomic  weight  of  crystallized  Kreatine  149      100.00 
0.3145   gm.   of  anhydrous  kreatine    yielded,  when  Anhydrous 

burned  with  oxide  of  copper,  0.4195  gm.  of  carbonic 

acid,  and  0.197  gm.  of  water. 

0.4085  gm.  of  anhydrous  kreatine,  burned  with  chro- 

mate  of  lead,  yielded  0.5590  gm.    of  carbonic   acid, 

and  0.2348  gm.  of  water. 

These  analyses  give  in   100  parts  (C :  N  —  8 :  3)  : 

I.  II. 

Carbon  ....        36.38  36.93 

Nitrogen 31.91  32.39 

Hydrogen         ....          696  6.96 

Oxygen 24.75  23.72 

100.00      100.00 
corresponding  to  the  formula, 

8  eq.  Carbon          .         .         .     -    .         48         36.64  its  formula. 

3  eq.  Nitrogen  ....    42        32.06 

9  eq.  Hydrogen  ...          9          6.87 

4  eq.  Oxygen  .         .         .         .32        24.43 

Atomic  weight  of  anhydrous  Kreatine  131      100.00 

The  crystallized  kreatine  corresponds,  therefore,  to 
the  formula, 

1  eq.   anhydrous  kreatine        .         .131         87.92  Formula  of 

2  eq.  water  ....  18         12.0b  the  crystals. 

149      100.00 
If  we  compare  the  formula  of  kreatine  with  that  of  Kreatine  and 

. glycocoll. 

the  formation  of  nitrous  acid  is  unavoidable,  and  the  excess  of 
carbon  in  the  above  analysis  arises,  no  doubt,  from  a  small 
quantity  of  nitrous  acid  which  had  escaped  the  reducing  action 
of  the  metallic  copper  in  the  anterior  part  of  the  tube. 

4* 


42  RELATIONS  OF  KREATINE. 

glycocoli  (sugar  of  gelatine),  it  appears  that   crystal- 
lized kreatine  contains  the  elements  of 

2  eqs.  glycocoll  ==  C8  N2  H8  Oe 
-f-  1  eq.  ammonia  =       N    Hs 

C8  N3  HU  Oe  * 

Kreatine  dissolves  easily  in  boiling  water,  and  a  solu- 
tion saturated  at  212°  forms,  on  cooling,  a  mass  of 
small  brilliant  needles.  From  a  diluted  solution  it  crys- 

*  Kreatine  contains  the  elements  of  the  Lactamide  of  Pelouze, 
and  Urea,  as  Liebig  has  suggested  in  a  letter  to  Gay-Lussac, 
which  was  published  in  the  "  Comptes  Rendus  "  of  last  year. 

Kreatine.  Lactamide.  Urea. 

C8  HH  N3  O6  =  C6  H7  N  O4  +  C2  H4  Na  O2. 
Lactamide  is  lactic  acid  or  lactic  sugar  in  which  one  atom  of 
oxygen  has  been  replaced  by  an  atom  of  amidogen. 
Lactic  acid.  Lactamide. 

C6  H5  O5  —  O  -f  N  H2  =  C6  H7  N  O4. 

Lactamide  contains  the  elements  of  glycocoll  and  oxide  of 
methyle. 

Lactamide.         Glycocoll.    Oxide  of  Methyle. 
C6  H7  N  O4  =  C4  H4  N  O3  -f  C2  H3  O. 

Glycocoll  has  been  resolved  by  a  current  of  electricity  into 
ammonia  and  aconitic  acid  (?). 

Glycocoll.    Ammonia.  Aconitic  Acid. 
C4  H4  N  O3  =  N  H3  +  C4  H  O3. 

Kreatine  may  be  considered  as  having  the  elements  of  urea, 
oxide  of  methyle,  aconitic  acid,  and  ammonia. 


Kr^ine.  Urea. 

C8  Hn  N3  O6  =  C2  H4  N2  02  -j-  C2  H3  O  +  C4  H  O3  4-  N  H3. 
Urea  with  two  atoms  of  water  contains  the  elements  of  car- 
bonic acid  and  ammonia.  v 

Urea. 

C2  H4  N2  02  4-  2  H  O  =  2  C  02  4-  2  N  H3. 
These  relations  are  interesting  to  contemplate,  when  we  recol- 
lect that  kreatine,  milk  sugar,  urea,  carbonic  acid,  ammonia,  and 
glycocoll,  as  abenzoate  in  the  form  of  hippuric  acid,  are  found  in 
the  liquid  excrements  of  man.  —  E.  N.  H. 


PROPERTIES  OF  KREATINE.  43 

tallizes  very  slowly,  in  somewhat  large  crystals,  often 
from  2  to  3  lines  in  length  and  1  line  in  thickness, 
which  increase  in  size  for  24  hours  after  cooling,  if  left 
in  the  liquid. 

1,000  parts  of  water  at  64.4°  dissolve  13.44  parts  of 
kreatine  ;  or  1  part  of  kreatine  dissolves  in  74.4  parts 
of  water. 

In  cold  alcohol  kreatine  is  nearly  insoluble,  1  part 
requiring  9,410  parts  of  alcohol  for  solution.  In  weak- 
er spirits  of  wine  it  is  rather  more  soluble. 

The  cold  aqueous  solution  of  kreatine  possesses, 
from  the  small  quantity  of  dissolved  matter,  a  weak, 
bitter  taste,  followed  by  a  somewhat  acrid  sensation  in 
the  throat.  When  the  aqueous  solution  of  kreatine 
contains  a  trace  of  foreign  organic  matter,  it  decom- 
poses very  readily,  as  Chevreul  observed.  Mouldy  veg- 
etations appear,  and  the  liquid  acquires  an  offensive, 
nauseous  odour. 

No  quantity,  however  large,  of  kreatine  can  destroy  Kreatine  is 

V  _b  J    neither  acid 

the  acid  reaction  even  of  the  weakest  acids  ;  it  possess-  nor  basic, 
es  no  basic  characters.  It  dissolves  easily  with  the 
aid  of  heat  in  barytic  water,  and  crystallizes  from  it 
unchanged.  The  crystals  which  are  deposited  contain 
no  baryta,  and  all  the  baryta  in  the  solution  is  precipi- 
tated by  carbonic  acid.  But  when  boiled  with  baryta 
water,  kreatine  is  decomposed ;  ammonia  is  disen- 
gaged ;  the  liquid  becomes  turbid,  even  when  the  air 
is  entirely  excluded,  and  there  is  deposited  carbonate 
of  baryta  in  crystalline  grains,  the  quantity  of  which 
progressively  increases  as  the  boiling  is  continued. 

In  the  warm  saturated  solution  of  kreatine,  the 
color  of  hyperoxide  of  lead  is  not  changed,  not  even 
when  boiled ;  the  crystals  of  kreatine  deposited  in  cool- 
ing are  free  from  oxide  of  lead.  A  solution  of  hyper- 
manganate  of  potash,  in  which  kreatine  is  dissolved, 


44  KREATININE. 

only  loses  its  red  color  by  long  digestion  with  the  aid  of 
heat,  without  perceptible  disengagement  of  gas.  The 
liquid  now  contains  no  kreatine,  and  gives  on  evapora- 
tion white  crystals ;  while  the  potash  is  found  partly 
combined  with  carbonic  acid. 

Action  of  The  action  of  strong  mineral  acids  is  very  remarka- 

kreatine.  ble.  A  solution  of  kreatine,  to  which,  while  cold,  hy- 
drochloric acid  is  added,  gives  by  spontaneous  evapora- 
tion crystals  of  unchanged  kreatine.  But  when  heated 
with  strong  hydrochloric  acid,  a  solution  of  kreatine  no 
longer  yields  crystals  of  that  substance.  The  same  re- 
sult is  obtained  with  sulphuric,  phosphoric,  and  nitric 
acids.  When  kreatine  is  dissolved  in  one  of  these  acids, 
and  the  solution  gently  evaporated,  crystals  are  obtain- 
ed, which  are  very  soluble  in  alcohol,  a  property  not 
belonging  to  kreatine.  These  crystals  contain  a  por- 
tion of  the  acid  employed,  in  a  state  of  combination. 
Kreatinine.  There  is  formed,  in  this  reaction  from  kreatine,  by  a 
transformation  of  its  elements,  caused  by  contact  with 
strong  mineral  acids,  a  new  body  of  totally  different 
chemical  properties,  a  true  organic  alkali,  which  I  shall 
call  kreatinine. 

Kreatinine. 
Formation  of      When  crystallized  kreatine  is  exposed,  in  the  drying 

kreatinine,  .        .       , 

by  means  of  apparatus  described  by  me,  to  a  current  of  dry  hydro- 
acid™C  C  chloric  acid  gas,  at  the  temperature  of  212°,  the  weight 
of  the  apparatus  at  first  increases;  but  by  continuing 
the  heat  and  the  current  of  gas,  the  original  weight  is 
at  last  very  nearly  recovered.  Although  it  thus  ap- 
pears as  if  kreatine,  under  these  circumstances,  could 
absorb  no  hydrochloric  acid,  this  conclusion  is  at  once 
found  to  be  erroneous,  because  during  the  whole  con- 
tinuance of  the  experiment  water  is  seen  to  pass  ofT,  till 
the  weight  of  the  apparatus  becomes  constant.  If  an- 


KREATIXINE.  45 

hydrous  kreatine  be  used  for  this  experiment,  an  in- 
crease of  weight  is  found  to  take  place. 

The  compound  formed  in  these  circumstances  is 
neutral  hydrochlorate  of  kreatinine. 

In  like  manner,  hydrochlorate  of  kreatinine  is  ob- 
tained, when  kreatine  is  covered  with  concentrated 
hydrochloric  acid  in  a  porcelain  dish,  and  the  solu- 
tion evaporated  in  the  water-bath  till  all  uncombined 
hydrochloric  acid  is  dissipated. 

When  kreatine  is  mixed  with  diluted  sulphuric  acid  or  by  means 
(for  1  part  of  kreatine,  1  part  of  an  acid,  composed  of  acid"  P  " 
27  parts  oil  of  vitriol,  and  73  parts  water),  the  solution 
being  evaporated  to  dryness,  and  heated  till  all  moisture 
is  expelled,  neutral  sulphate  of  kreatinine  is  left. 

From  the  hydrochlorate  or  the  sulphate,  prepared  in 
either  of  the  above  ways,  kreatinine  may  be  easily  ob- 
tained. 

When   carbonate   of  baryta  is   added  to  a  boiling  Separation  of 
aqueous  solution  of  the  sulphate  of  kreatinine,  till  no  from  the  sui- 
more  effervescence  ensues,  and  the  liquid  has  an  alka-  p 
line  reaction,  sulphate  of  baryta  is  deposited,  and  pure 
kreatinine  remains  in  solution. 

From  the  hydrochlorate  the  base  is  obtained,  when  and  from  the 

J  ...  hydrochlo- 

the  aqueous  solution  of  the  salt  is  boiled  with  hydrated  rate, 
oxide  of  lead.  The  hydrochlorate  is  dissolved  in  from 
24  to  30  parts  of  water,  the  solution  heated  to  boiling 
in  a  porcelain  vessel,  and  hydrated  oxide  of  lead  sus- 
pended in  water  is  added  in  small  portions.  At  first 
chloride  of  lead  is  formed,  and  the  liquid  retains  its 
acid  reaction;  but  when  more  oxide  of  lead  is  added, 
it  becomes  neutral,  or  slightly  alkaline.  If  now  there 
be  added  to  the  mixture  a  quantity  of  oxide  of  lead 
three  times  as  great  as  that  already  employed,  and  the 
whole  is  kept  boiling  for  some  time,  a  point  is  at  last 
reached  at  which  the  liquid,  no  matter  how  much  di- 


46  PROPERTIES  OF  KREATININE. 

luted,  seems  to  be  converted  into  a  thick,  light,  yellow 

pasty  mass.     The  decomposition  is  then  complete  ;  the 

liquid    is   filtered  and   the    residue   carefully  washed. 

Purification     Should  a  trace  of  oxide  of  lead  be  dissolved  or  sus- 

of  kreatinine.  . 

pended  in  the  filtered  liquid,  it  is  easily  removed  by 
means  of  a  little  animal  charcoal.  This  process  de- 
pends on  the  conversion  of  the  chloride  of  lead  into  a 
basic  compound  with  oxide  of  lead,  which  is  as  insolu- 
ble in  water  as  chloride  of  silver. 

The  solution  of  kreatinine  thus  obtained  is  entirely 
free  from  chlorine,  and  yields,  as  does  also  the  solution 
prepared  from  the  sulphate  by  baryta,  on  evaporation, 
perfectly  formed  crystals  of  kreatinine. 

As,  in  both  methods,  all  the  impurities  contained  in 
the  carbonate  of  baryta,  or  in  the  oxide  of  lead,  which 
may  contain  acetic  acid  or  potash,  are  left  in  the  solu- 
tion of  kreatinine,  it  is  necessary  to  bestow  particular 
attention  on  the  perfect  purification  of  the  carbonate  of 
baryta  or  hydrated  oxide  of  lead,  which  are  to  be  used 
for  this  purpose. 

Description  The  crystals  of  kreatinine  belong  to  the  monoklino- 
tais.he  °rys  metric  system,  and  are  formed  by  the  prism  oo  P,  the 
basic  terminal  face  o  P,  and  klinodiagonal  terminal  face 
oo  P  QO  .  The  orthodiagonal  is  less  than  the  klinodiag- 
onal. The  angle  o  P  :  QD  P  oo,  that  is,  the  angle  of 
inclination  of  the  principal  axis  on  the  klinodiagonal, 
was  found  to  be  =  69°  24' ;  the  angle  under  which  the 
lateral  faces  oo  P  meet  in  the  orthodiagonal  section  = 
98°  20',  and  in  accordance  with  this,  the  angle  which 
oo  P  oo  forms  with  oo  P  =  130°  50'.* 

Kreatinine  is  much  more  soluble  in  cold  water  than 
kreatine.  1,000  parts  of  water  dissolve  87  parts  of 

*  The  cry  stall  ometric  measurements  given  in  this  work  have 
been  made  by  Dr.  Kopp. 


PROPERTIES    OF    KREATININE.  47 

•i 

kreatinine,  or  1  part  dissolves  in  11.5  parts  of  water  at 
60°.  In  hot  water  it  is  much  more  soluble. 

The  aqueous  solution  restores  the  blue  of  reddened 
litmus  paper,  and  a  crystal,  laid  on  moist  turmeric  pa- 
per, causes  a  brown  stain  at  the  point  of  contact. 

Kreatinine  dissolves  in  boiling  alcohol,  and  crystal- 
lizes on  cooling.  1,000  parts  of  alcohol  at  60°  dissolve 
9.8  parts  of  kreatinine. 

In  its  chemical  character,  kreatinine  is  quite  analo-  Kreatinine  i* 

analogous  to 
gO US  to  ammonia.  ammonia. 

A  moderately  concentrated  solution  of  nitrate  of  sil-  its  action  on 

.    .          .          iii  •  i        n  nitrate  of  sil- 

ver, when  kreatinine  is  added  to  it,  instantly  forms  a  Ver, 

mass  of  small  white  needles,  which  are  very  soluble  in 
hot  water,  and  crystallize  from  it  unchanged  on  cooling. 
They  are  a  basic  compound  of  kreatinine  and  nitrate 
of  silver. 

In  a  solution  of  corrosive  sublimate,  kreatinine  causes  on  corrosive 

....  „  .        sublimate, 

at  once  a  white  curdy  precipitate,  which,  in  a  few  min- 
utes, changes  to  a  mass  of  slender  transparent  colorless 
needles. 

In  a  neutral  aqueous  solution  of  chloride  of  zinc,  on  chloride  of 
kreatinine  causes  instantly  a  precipitate  formed  of  crys- 
talline grains,  appearing  under  the  microscope  as  round 
masses,  formed  of  very  small  needles  concentrically 
grouped. 

Kreatinine  expels  ammonia  from  ammoniacal  salts,  on  salts  of 
and  forms  with  salts  of  oxide  of  copper  crystallizable  JSu^Tsaits 
double  salts  of  a  fine  blue  color.  of  copper, 

Bichloride  of  platinum,  when  hydrochlorate  of  krea-  On  bichloride 
tinine  is  added  to  it,  causes  no  precipitate  if  the  solution  of  plat 
is  diluted  ;  but  on  evaporation  in  a  gentle  heat,  there 
are  formed  deep  yellow  transparent  crystals  of  consid- 
erable size,  very  soluble  in  water,  less  so  in  alcohol. 

A  solution  of  kreatinine,  to  which  bichloride  of  plati- 
num and  hydrochloric  acid  have  been  added,  yields, 


48  COMPOSITION    OF    KREATININE. 

when   evaporated,    the    same   compound,  which   is    a 
double  salt  analogous  to  the  double  chloride  of  plati- 
num and  ammonium. 
The  composi-       The    composition    of  kreatinine    is    easily    deduced 

tion  of  krea-    f  ,  .  r*  ,       ^        ,  *>      -  •  •* 

tiuine  de-       irom  the  action  or  hydrochloric  acid  gas  on  kreatme. 

duced  from  /\  ei-we  (*     i 

its  formation.  0.5/75  gm.  of  kreatme  in  crystals  increased  in 
weight  when  exposed  to  a  current  of  that  gas,  at  202°, 
by  only  0.002  gm.  The  residue,  dissolved  in  water, 
and  precipitated  by  nitrate  of  silver,  gave  0.5605  gm. 
chloride  of  silver,  corresponding  to  24.68  per  cent,  of 
hydrochloric  acid. 

The  fact  that  the  weight  is  not  altered  in  this  exper- 
iment implies,  that,  for  24.68  parts  of  hydrochloric  acid 
absorbed,  an  equal  or  very  nearly  equal  weight  of  wa- 
ter has  been  expelled. 

Now  since  crystallized  kreatine,  when  heated  alone 
to  212°,  loses  12.08  per  cent.' of  water,  it  is  evident 
that  twice  this  quantity  has  been  expelled,  because  oth- 
erwise, when  24.68  per  cent,  of  hydrochloric  acid  had 
been  absorbed,  the  weight  must  have  increased.  Since, 
moreover,  1  eq.  of  hydrochloric  acid  weighs  36.5 
(H  =  1)  and  that  weight  corresponds  to  4  eq.  of  wa- 
ter, it  follows  that  for  1  eq.  of  hydrochloric  acid  ab- 
sorbed, 4  eqs.  of  water  have  been  expelled. 

It  follows  further,  that  anhydrous  kreatine  must  gain 

in  weight,  when  exposed  to  hydrochloric   acid   gas,  to 

the  amount  of  14.05  per  cent.     In  fact.  0.5820  gm.  of 

anhydrous  kreatine,  under  these  circumstances,  absorb 

0.084  gm.  of  hydrochloric  acid,  corresponding  to  14.46 

per  cent.,  a  coincidence  as  close  as  could  be  obtained. 

Kreatine,  in        The  conversion  of  kreatine  into  kreatinine,  by  the 

atiSnc?  loses  action  of  mineral  acids,  depends,  therefore,  on  the  sep- 

ter?8        L    aration  of  4  eqs.  of  water.     If  we  subtract  these  from 

the  formula  of  crystallized  kreatine,  the  composition  of 

kreatinine  in  100  parts  is  as  follows :  — 


ANALYSIS    OF    KREATININE.  49 

Formula, 


8  eqs.  Carbon        =  48 
3  eqs.  Nitrogen     =  42 
7  eqs.  Hydrogen  =     7 
2  eqs.  Oxygen       =  16 

42.48 
37.17 
619 
14.16 

Atomic  weight  of  ) 
Kreatinine  ....  5 

In  accordance  with  this  theoretical  result,  there  were  Analysis  »f 
obtained  by  combustion  with  chromate  of  lead  the  fol- 
lowing numbers  :  — 

0.3418  gm.  of  kreatinine  yielded  0.5332   gm.  car- 
bonic acid,  and  0.1965  gm.  water. 
{..  The  same  substance  yielded,  when  burned,  a  gaseous 
mixture,  in  which,  for  434  volumes  of  nitrogen  gas, 
there  were  found  1,132  vol.  of  carbonic  acid.* 
According  to  this  analysis,  kreatinine  contains 
Carbon         .         .         .        42.54 
Nitrogen          .         .         .     37.20 
Hydrogen    .         .         .          638 
Oxygen  .        .        .     13.88 

100.00 

If  we  compare  with  the  formula  of  kreatinine  that  Kreatinine 
of  caffeine  (theine),  it  appears  that  kreatinine  contains  andcaflfelne- 
the  elements  of  1  atom  of  caffeine  -j-  1  atom  amide. 
Caffeine  is 

C8  N2  H5  O2  :  add  to  this 
1  at.  Amide     N  H2 

The  sum  is  Cs  Na  HT  O2  =  1  at.  Kreatinine. 


N. 

CO52. 

*  The  2d  tube 

yielded 

75 

for 

187 

3d 

u 

77 

it 

197 

4th 

it 

79 

it 

207 

5th 

(C 

48 

(C 

126 

6th 

n 

70 

(C 

200 

7th 

cc 

85 

u 

215 

N  :  C  O2  = 

3:8    434 

u 

1132 

5 

50  KREATINE    AND    KREATININE    ARE 

Kreatine  and  Kreatinine,  constituents  of  human  urine. 
The  com-  If  we  compare  the  results  of  the  analysis  of  kreatine 

pound  discov-          ,    ,  .    .  .  ,       , 

ered  in  urine  and  kreatinme  with  the  composition  of  the  substance 
fer  e        }"  discovered  three  years  since  by  Pettenkofer  *  in  human 
urine,  and  analyzed  by  him,  we  perceive  at  once,  that 
both  kreatine  and  kreatinine  must  stand  in  a  definite 
relation  to  that  body.     Pettenkofer  found  that  this  sub- 
stance, when  burned,  yielded  a  gaseous  mixture,  con- 
taining, for  8  vol.  of  carbonic  acid,  3  vol.  of  nitrogen, 
contains  the    This  is  the  same  proportion  as  is  contained  in  kreatine 
tions  of  car-r    and  kreatinine  ;  although,  on  the  other  hand,  he  found 

bon  and  ni-  .     .         .        ,  .  „  .      .  . 

trogen  as        a  variation  in  the  proportion  of  hydrogen  and  oxygen. 

kreatinine!  The  substance  from  urine  contains  1  eq.  of  water  less 
than  anhydrous  kreatine  and  1  eq.  more  than  kreati- 
nine. 

Although  I  had  no  reason  to  doubt  the  accuracy  of 
Pettenkofer's  analysis,  yet  I  considered  it  desirable  to 
compare  the  properties  of  the  substance  from  urine 
with  those  of  kreatine  and  kreatinine. 

pettenkofer'a  According  to  Pettenkofer's  process  for  its  prepara- 
tion, fresh  human  urine  is  neutralized  with  carbonate 
of  soda,  evaporated  till  the  salts  crystallize  out,  then 
extracted  by  alcohol,  and  mixed  with  a  concentrated 
solution  of  chloride  of  zinc.  In  this  mixture  there  are 
deposited,  after  some  hours  or  days,  small  granular 
hard  crystals,  frequently  in  crusts,  which  contain  chlo- 
ride of  zinc  and  a  crystallizable  organic  substance. 
When  these  crystals  are  dissolved  in  hot  water,  the 
zinc  separated  by  means  of  baryta,  the  filtered  liquid 
.  evaporated,  the  residue  acted  on  by  alcohol,  the  alco- 
holic solution  deprived  of  baryta  by  sulphuric  acid,  and 
the  liquid,  which  now  contains  hydrochloric  acid,  sul- 

*  Annalen  der  Chemie  und  Pharmacie,  Vol.  LII.  p.  97. 


CONSTITUENTS    OF    HUMAN    URINE.  51 

phuric  acid,  and  the  organic  compound,  boiled  with 
oxide  of  lead,  the  sulphuric  and  hydrochloric  acids  are 
thus  separated,  and  the  organic  compound  remains  dis- 
solved in  alcohol,  and  gives  on  evaporation  a  crystal- 
line white  mass,  which  instantly  reproduces  the  original 
crystalline  precipitate  when  its  solution  is  mixed  with 
chloride  of  zinc. 

According  to  my  experiments,  this  substance  may  be  simpler  pro- 

...-»-  ,  i  rrn  •         cess  proposed 

obtained  from  urine  by  a  simpler  process.  1  he  urine  by  the  au- 
is  neutralized  by  milk  of  lime,  and  then  solution  of 
chloride  of  calcium  is  added  as  long  as  it  causes  a  pre- 
cipitate of  phosphate  of  lime.  The  liquid  is  then  fil- 
tered and  evaporated  till  the  salts  crystallize  out  on 
cooling.  The  mother  liquor  is  separated,  without  the 
use  of  alcohol,  from  the  salts,  and  mixed  with  a  syrupy 
solution  of  neutral  chloride  of  zinc,  in  the  proportion  of 
about  \  ounce  to  1  Ib.  of  the  extract. 

After  three  or  four  days,  the  greater  part  of  the  zinc 
compound  of  Pettenkofer  is  found  to  have  crystallized 
in  rounded  yellow  grains.  The  deposit  is  well  washed 
with  cold  water,  then  dissolved  in  boiling  water,  and 
hydrated  oxide  of  lead  added  to  the  solution,  till  it  ac- 
quires a  strong  alkaline  reaction.  By  this  means  the 
zinc  and  hydrochloric  acid  are  separated  in  an  insoluble 
form,  while  the  substance,  formerly  combined  with 
them,  remains  in  solution.  This  is  now  acted  on  with 
blood -charcoal,  which  removes  a  yellow  coloring  mat- 
ter and  a  trace  of  oxide  of  lead,  and  the  filtered  liquid 
is  evaporated  to  dryness. 

By  the  process  of  Pettenkofer,  as  well  as  by  that  Pettenkofer's 

J  r  .  .  substance    is 

just  described,  there  was  obtained  a  white  crystalline  a  mixture  of 

*  kreatinine 

substance,  having,  in  each  case,  the  same  characters,  with  a  little 

.     kreatine. 

But  a  closer  investigation  immediately  showed  that  this 
substance  was  a  mixture  of  two  compounds  of  different 
properties,  which  may  easily  be  separated  by  means  of 


O^  ANALYSIS    OF    THE 

alcohol,  one  of  them  being  easily  soluble,  the  other 
very  sparingly  soluble,  in  hot  alcohol.  When  a  por- 
tion of  the  mixed  substance  is  boiled  with  8  or  10 
times  its  weight  of  alcohol,  either  a  part  remains  un- 
dissolved,  or  the  solution  is  complete,  but  deposits  crys- 
tals on  cooling.  These  crystals  are  found  to  be  identi- 
cal with  the  undissolved  residue.  When  they  are  sep- 
arated from  the  mother  liquor,  and  the  latter  evapo- 
rated, a  new  crystallization,  of  different  form  and  prop- 
erties, is  obtained.  The  body  which  crystallizes  first, 
or  remains  in  the  undissolved  residue,  contains  water  of 
crystallization  and  has  no  action  on  vegetable  colors  ; 
the  more  soluble  has  in  its  aqueous  solution  a  strong 
alkaline  reaction,  its  crystals  do  not  effloresce  when 
heated,  and  the  analysis  of  these  two  compounds 
showed,  as  the  external  form  and  chemical  characters 
Analyse  of  indicated,  that  the  one  which  first  crystallized  was 

the  com- 
pounds from  kreatine,  the  other  kreatinine.     The  kreatine  thus  pre- 
pared from  urine  yielded,  when  burned  with  oxide  of 
copper,  a  gaseous  mixture  containing,  for  3  vols.  of 
nitrogen,  8  vols.  of  carbonic  acid.* 

0.6085  gm.  lost,  at  212°,  0.0775  gm.  of  water,  = 
12.77  per  cent. 

0.3686  gm.  yielded  0.500  gm.  of  carbonic  acid  and 
0.2348  gm.  of  water. 

That  ingredient  of  Pettenkofer's  substance  which 
was  most  soluble  in  alcohol  (kreatinine)  gave,  when 
burned,  a  gaseous  mixture  in  which  nitrogen  and  car- 

N.        COa. 

*  The  2d  tube  yielded  72  for  190 
3d  "  78  "  205 

4th          "  74   "   198 

5th         "  55  "  202 

6th         "  86  "   177 

365  «   972 


COMPOUNDS    FROM    URINE.  53 

bonic  acid  were  in  the  proportion  of  280  N  to  740 
C  O2,  or  of  3  vols.  nitrogen  to  8  vols.  carbonic  acid.* 
Further,  0.3767  gm.  of  the  same  body  yielded  0.589 
gm.  carbonic  acid  and  0.2112  grn.  water. 

The  composition  of  these  two  substances  in  100  parts  Composition 

of  the  sub- 
is,  therefore,  stances  from 

Kreatine  from  Kreatinine 

Urine  (anhydrous).  from  Urine. 

Carbon         .         .        .        36.90  42.64 

Nitrogen          .         .         .     32.61  37.41 

Hydrogen    .         .         .          7.07  6.23 

Oxygen           .         .         .    23.42  13.72 

100.00  100.00 

If  we  compare  these  numbers  with  those  obtained  by  They  are 
the  analysis  of  kreatine   from  flesh,  and  the  analysis  wi^ 


of  the  kreatinine  prepared  from  it,  it  is  obvious  that  kreatinine. 
they   are   respectively   identical,   and    indeed   no   dif- 
ference can  be  detected  in  the  physical  and  chemical 
characters  of  the  two  substances  from  urine  and  those 
from  flesh. 

It  has  been  stated,  that  the  two  substances  which 
served  for  the  preceding  analysis  were  obtained  from 
fresh  urine  ;  but  it  seemed  ta  me  to  be  interesting,  to 
ascertain  the  influence  which  the  putrefaction  of  the 
urine  has  on  these  substances. 

When  putrid  urine,  in  which,  of  course,  all  the  urea  in  the  putre- 

,     .  .  „  .         .     faction  of 

has    been   converted    into   carbonate   of    ammonia,   is  urine,  the 
boiled  with  milk  of  lime  till  ammonia  is  no  longer  dis-  alone  disap- 
engaged,  then  filtered,  evaporated  to  a  thin  syrup,  and  ** 
in  this  state  mixed  with  chloride  of  zinc,  there   sep- 

N.      c  02. 

*  The  2d  tube  yielded  52  for  142 

3d  "  71   «   189 

4th         "  69   "    183 

5th          "  88   "   226 

280  "   740 


54          FORMATION    OF    PETTENKOFEtt's    COMPOUND. 

arates  in  the  course  of  a  few  days  a  considerable  quan- 
tity of  a  yellow  granular  compound,  which  contains 
chlorine  and  zinc,  and  under  the  microscope  cannot  be 
distinguished  from  the  compound  formed  by  chloride  of 
zinc  in  fresh  urine.  When  dissolved  in  boiling  water, 
and  deprived  of  chloride  of  zinc  and  coloring  matter 
by  means  of  hydrated  oxide  of  lead  and  blood-char- 
coal, the  organic  substance  contained  in  it  was  found  to 
be  kreatinine,  without  a  trace  of  kreatine. 

During  the  putrefaction  of  urine,  therefore,  the 
kreatine  is  destroyed,  while  the  kreatinine  suffers  no 
change. 

I  consider  kreatine  to  be  an  accidental  and  variable 
ingredient  of  Pettenkofer's  zinc  compound ;  for  a  warm 
(not  boiling)  solution  of  kreatine  is  not  precipitated  by 
chloride  of  zinc,  and  the  crystals  which  are  deposited 
contain  neither  zinc  nor  chlorine,  but  possess  all  the 
characters  of  pure  kreatine. 
Formation  of  It  is  clear  that  if  the  fresh  urine  contain  kreatinine 

Pettenkoler's   .  ...  .  ,  .  ,  ,     « 

compound,  in  combination  with  an  acid,  and  free  kreatine,  the 
kreatinine,  when  it  is  neutralized  by  an  alkali,  will  be 
set  free,  and  when  the  liquid  is  concentrated  to  ^tti  of 
its  original  volume,  the  addition  of  chloride  of  zinc 
will  precipitate  the  compound  of  chloride  of  zinc  with 
kreatinine  ;  but  the  crystals  of  this  substance  will  be 
mixed  with  those  of  kreatine,  whenever  the  quantity  of 
kreatine  present  is  more  than  the  liquid  can  retain  in 
solution  when  cold. 

Urine  is  an         Although  the  amount  of  kreatine  and  kreatinine  to 
source"©?31     be  obtained  from  urine  is  not  considerable,  yet  I  con- 
kreatin?neand  side  r^  the  preparation  of  these  substances  from  urine  to 
be    more   convenient,   and   especially  more    economi- 
cal, than  their  extraction  from  flesh  ;  and   by  either 
of  the  processes  just  described,  they  may  be  obtained 
in  any  required  quantity  by  operating  on  a  sufficiently 
large  scale. 


SALTS    OF    KREATININE.  55 

Hydrochlorate  of  Kreatinine.  —  This  salt,  the  prep-  Hydrochio- 

1-11  111           M      i      -r  rateofkrea- 

aration  of  which  has  been  already  described,  dissolves  tinine. 
readily  in  boiling  alcohol,  and  crystallizes  from  it  in 
short,  transparent,  colorless  prisms,  very  soluble  in 
water  ;  it  is  obtained  by  evaporating  its  aqueous  solu- 
tion in  broad  transparent  scales  of  an  acid  reaction. 
A  saturated  solution  of  this  salt  in  boiling  alcohol,  to 
which  ammonia  is  added  till  the  acid  reaction  is  de- 
stroyed, deposits  on  cooling  small  transparent  granular 
crystals  of  kreatinine. 

0.4764  gm.  of  hydrochlorate  of  kreatinine  yielded 
0.5677  gm.  carbonic  acid  and  0.227  water. 

Further,  0,542  gm.  yielded  0.513  gm.  chloride  of 
silver.  This  gives  in  100  parts, 

Calculated.          Found. 

8  eqs.  Carbon          .         .        48  32.30  32.48 

3  eqs.  Nitrogen  .         .    42  28.11  28.27 

8  eqs.  Hydrogen     .         .          8  5.35  5.30 

2  eqs.  Oxygen     .         ...     16  10.55  10.54 

1  eq.   Chlorine       .         .        35.4         23.69  23.41 

Atomic  Weight          .        .  149.4       100.00          100.00 
Chloride  of  Platinum  with  hydrochlorate  of  kreati-  Double  salt 
nine.  —  A  solution  of  hydrochlorate  of  kreatinine  gives,  Jfd^of  piaiT- 
on  the  addition  of  bichloride  of  platinum,  and   gentle  ni 
evaporation,   aurora-red    prisms    of    the    double    salt. 
When  more  rapidly   formed,  this  salt  is  obtained    in 
yellowish-red  transparent  grains. 

0.6086  gm.  of  this  salt,  made  with  kreatine  prepared 
from  flesh,  left  after  ignition  0.1858  gm.  platinum. 

0.8608  gm.  of  the  same  salt,  prepared  with  Petten- 
kofer's  compound,  derived  from  urine,  left  0.2665  gm. 
platinum. 

Hence  this  double  salt  consists  of 

Calculated.  Found. 

Kreatinine  and  Hydrochloric  acid        69.05         ^69.47         69.05 

Platinum 30.95         30.53         30.95 

100.00        100.00        100.00 


56  SARCOSINE. 

sulphate  of  Sulphate  of  Kreatinine.  —  A  boiling  saturated  solu- 
tion of  kreatinine,  to  which  diluted  sulphuric  acid  is 
added,  till  a  strong  acid  reaction  appears,  gives  on 
evaporation  a  white  saline  mass,  easily  dissolved  by  hot 
alcohol.  While  cooling,  the  solution  becomes  milky, 
and  deposits  (on  becoming  clear)  transparent,  concen- 
trically-grouped, four-sided  tables  of  neutral  sulphate 
of  kreatinine,  the  crystals  of  which  salt  continue  trans- 
parent when  heated  to  212°. 

0.439  gm.  of  sulphate  of  kreatinine  yielded  0.315 
gm.  of  sulphate  of  baryta. 

0.5655  gm.  of  the  same  salt  gave,  when  burned, 
0.6085  gm.  of  carbonic  acid,  and  0.2563  gm.  of  water. 

Hence  this  salt  consists  of 


Calculated. 

Found. 

1  eq.  Sulphuric  acid 

40 

24.69 

24.65 

f  8  eq.  Carbon 

48 

29.63 

29.33 

.,         tr       •   .             !  3  eq.  Nitrogen 
1  eq.  Kreatinine        J 
i  8  eq.  Hydrogen 

42 

8 

25.92 
4.94 

25.44 
5.03 

[3eq.  Oxygen 

24 

14.82 

15.55 

1  eq.  Sulphate  of  Kreatinine  =  162        100  00        100.00 
Sarcosine. 

Action  of          When  to  a  boiling  saturated  solution  of  kreatine  we 
t^watefori  a(^  ten  times  the  weight  of  the  kreatine  of  crystal- 
kreatme.       Jized  hydrate  of  baryta,  the  solution  continues  clear  at 
first,  but  by  continued  boiling  it  becomes  turbid,  and 
deposits  a  white  crystalline  powder,  adhering  to  the 
sides  of  the  vessel,  which  increases  as  long  as  the  dis- 
engagement of  ammonia  continues.     If  the  boiling  be 
continued,  baryta  and  water  being  added  from  time  to 
time,  until  no  further  escape  of  ammonia  is  perceptible, 
there  is  obtained   by  filtration  a  transparent  colorless 
liquid,  which  contains  caustic  baryta  along  with  a  new 
organic   base,   to   which   I   have   given   the   name   of 
Sarcosine.      Sarcosine.     The  white  powder  remaining  on  the  filter 


PURIFICATION    OF    SARCOSINE.  57 

contains  no  organic  matter,  and  is  pure  carbonate  of 
baryta. 

By  passing  a  current  of  carbonic  acid  gas  through  l\s  purifica- 
the  liquid,  and  subsequently  boiling,  the  baryta  is  sepa- 
rated from  the  new  base,  which  remains  dissolved  ;  and 
the  solution,  when  evaporated,  gives  a  syrup,  which  on 
standing  consolidates  into  a  mass  of  broad,  colorless, 
transparent  plates.  For  the  preparation  of  pure  sarco- 
sine,  it  is  important  to  use  perfectly  pure  baryta,  previ- 
ously tested  for,  and  if  necessary  deprived  of,  traces  of 
potash,  lime,  chlorine,  or  nitric  acid ;  because  all  such 
impurities  accumulate  in  the  sarcosine,  from  which  they 
cannot  easily  be  removed. 

To  obtain  pure  sarcosine,  it  is  advisable  to  convert  it, 
as  prepared  by  the  process  just  described,  into  sulphate. 
For  this  purpose,  diluted  sulphuric  acid  is  added  to  the 
base  obtained  by  the  evaporation  of  the  filtered  liquid, 
till  it  acquires  a  strong  acid  reaction.  The  acid  solution 
is  evaporated  in  the  water-bath,  and  to  the  syrupy  resi- 
due alcohol  is  added,  and  well  mixed  with  it  by  means 
of  a  glass  rod.  The  syrupy  sulphate  is  thus  converted 
into  a  white  crystalline  powder,  which  is  well  washed 
with  cold  alcohol,  then  dissolved  in  water,  and  the  solu- 
tion digested  with  pure  carbonate  of  baryta  in  a  warm 
place,  till  no  further  effervescence  ensues,  and  the  acid 
reaction  has  disappeared.  The  liquid  now  contains  the 
pure  base  dissolved  ;  it  is  filtered  from  the  sulphate  and 
carbonate  of  baryta,  evaporated  in  the  water-bath  to  a 
syrup,  and  in  this  state  set  aside.  The  sarcosine  crys- 
tallizes in  from  24  to  36  hours. 

The  crystals  of  sarcosine  are  right  rhombic  prisms  ;  crystals  of 
acuminated  on  the  ends  by  surfaces  set  perpendicular 
on  the  obtuser  angles  of  the  prism,  that  is,  the  combi- 
nation oo  p  :  P  OD.     Only  the    faces   oo  P   had   lustre 
enough  to  admit  of  approximative  measurement;  the 


58 


ANALYSIS    OF    SARCOSINE. 


Analysis  of 
sarcosine. 


Formula  of 
sarcoeine. 


angles  of  the  prism  were  found  =  103°  and  77°.  Sin- 
gle planes  of  P  and  o  P  occur  rarely,  and  then  doubt- 
fully indicated.  The  crystals  are  colorless,  perfectly 
transparent,  and  of  considerable  size.  They  are  ex- 
tremely soluble  in  water,  very  sparingly  soluble  in  alco- 
hol, and  insoluble  in  ether.  When  dried  at  212°,  they 
retain  their  original  aspect ;  at  a  somewhat  higher  tem- 
perature they  melt,  and  sublime  without  residue.  When 
some  crystals  of  sarcosine  are  exposed,  between  two 
watch-glasses,  for  a  long  time,  to  a  heat  of  212°,  the 
upper  glass  is  covered  with  a  network  of  crystals  of 
sublimed  sarcosine. 

The  analysis  of  sarcosine  gave  the  following  results. 
When  burned  with  the  oxide  of  copper,  it  gave  a  gase- 
ous mixture,  containing  1  vol.  of  nitrogen  for  6  vols.  of 
carbonic  acid.*  It  therefore  contains,  for  6  eqs.  of 
carbon,  1  eq.  of  nitrogen. 

0.3843  gm.  of  sarcosine  yielded,  further,  0.574  gm. 
of  carbonic  acid,  and  0.2735  gm.  of  water. 

0.3666  gm.  yielded  0.550  gm.  of  carbonic  acid,  and 
0.2578  gm.  of  water. 

This  gives  for  100  parts, 

Calculated.  Found. 


6  eq.  Carbon 

.    36        40.45 

40.73 

40.90 

1  eq.  Nitrogen 

14        15.73 

15.84 

15.90 

7  eq.  Hydrogen 

.      7          7.86 

7.90 

7.82 

4  eq.  Oxygen 

32        35.96 

35.53 

35.38 

1  eq.  Sarcosine 

.    89      100.00 

100.00 

300.00 

N. 

CO2. 

*  The  2d 

tube  yielded        42 

233 

3d 

"                    38 

241« 

4th 

"                    40 

230 

5th 

"                    40 

243 

6th 

«                    43 

252 

203 


1,199 


PROPERTIES  OF  SARCOSINE.  59 

The  aqueous  solution  of  sarcosine  has  no  action  on  properties  of 
vegetable  colors ;  it  has  a  sweetish,  sharp,  somewhat 
metallic  taste ;  in  diluted  solutions  of  nitrate  of  silver 
and  corrosive  sublimate  it  causes  no  change.  But  if  a 
crystal  of  sarcosine  be  placed  in  a  cold  saturated  solu- 
tion of  corrosive  sublimate,  it  is  instantly  dissolved,  and 
in  a  short  time  there  are  seen  to  be  formed  a  number  of 
slender  transparent  needles  of  a  double  salt,  which,  if 
the  quantity  of  sarcosine  is  not  too  small,  fill  the  whole 
liquid,  converting  it  into  a  semi-solid  mass.  A  solution 
of  acetate  of  copper  acquires,  by  the  addition  of  sarco- 
sine, the  same  deep  blue  color  as  is  caused  by  ammo- 
nia, and  by  gentle  evaporation  there  are  obtained  thin 
scales  of  the  same  color. 

When  evaporated  along  with  hydrochloric  acid,  sar-  Hydrochio- 
..  1-11-      i        -i       rate  °f  sar- 

cosine  yields  a  white  saline  mass,  which  dissolves  in  hot  cosine. 

alcohol,  and  is  deposited  on  cooling  in  small  transparent 
grains  and  needles. 

A  solution  of  hydrochlorate  of  sarcosine,  mixed  with  Double  salt 

m  J  .  .  .  with  bichlo- 

excess  of  bichloride  of  platinum,  gives  no  precipitate  ;  ride  of  piati- 

•  /»  n  J    num> 

but  by  spontaneous  evaporation  it  soon  forms  flattened 
octohedrons  of  a  honey-yellow  color,  which  often  ex- 
hibit faces  half  an  inch  broad,  lying  on  each  other  in 
the  manner  of  the  steps  of  stairs.  By  means  of  a 
mixture  of  alcohol  and  ether,  the  superfluous  bichloride 
of  platinum  is  easily  removed,  and  the  crystals  may 
thus  be  obtained  quite  pure. 

The  double  chloride  of  platinum  and  sarcosine,  dried  Analysis  of 

the  double 

in  the  air,  loses,  when  further  heated  to  212°,  6.7  per  salt. 
cent,  of  water. 

0.4544  gm.  of  the  anhydrous  salt  yielded,  on  ignition, 
0.1527  gm.  of  platinum. 

If  this  salt  have  a  composition  analogous  to  that  of 
the  double  chloride  of  platinum  and  ammonium,  it 
would  contain 


60 


SALTS    OF    SARCOSINE. 


Its  formula. 


Sulphate  of 
sarcosiae. 


Analysis  of 
the  sulphate. 


89.0) 
36.4  > 

70.8) 


196.2 


In  100  Parts. 
Theory.  Experiment. 

66.55        66.40 


98.7        33.45        33.60 


1  eq.  Sarcosine 

1  eq.  Hydrochloric  acid 

2  eqs.  Chlorine 
1  eq.  Platinum 

1  eq.  of  the  anhydrous  double  salt       294.9       100.00       100.00 

The  loss  of  weight  at  212°  indicates  that  the  crystal- 
lized salt  contains  2  eqs.  of  water  =  5.7  per  cent. 

Sulphate  of  Sarcosine.  —  The  preparation  of  this  salt 
has  been  already  described  (p.  57).  When  the  resi- 
due, well  washed  with  cold  alcohol,  is  boiled  with  from 
10  to  12  times  its  weight  of  alcohol,  it  dissolves,  with 
the  exception  of  a  trace  of  sulphate  of  baryta  ;  and  this 
solution  deposits,  on  cooling,  transparent  colorless  four- 
sided  tables  of  high  lustre,  which  can  hardly  be  distin- 
guished by  their  aspect  from  chlorate  of  potash.  They 
are  sparingly  soluble  in  cold  alcohol,  but  very  soluble 
in  water,  and  crystallize  from  their  aqueous  solution  in 
large  feathery  plates.  Both  the  aqueous  and  alcoholic 
solutions  have  a  strong  acid  reaction,  so  that  it  is  diffi- 
cult to  tell  when  the  washing  of  them,  to  remove  un- 
combined  acid,  is  complete.  On  this  account,  the  fol- 
lowing analyses  of  this  salt  have  given  a  slight  excess 
of  sulphuric  acid. 

0.6928  gm.  of  sulphate  of  sarcosine  lost,  at  212°, 
0.049  gm.  of  water  =  6.54  p.  c. ;  and  yielded  0.5470 
gm.  of  sulphate  of  baryta  =  29.25  p.  c.  of  sulphuric 
acid  in  the  anhydrous  salt. 

0.5899  gm.  of  sulphate  of  sarcosine  lost,  at  212°, 
0.0385  gm.  of  water  =  7.07  p.  c. ;  and  gave  0.4870 
gm.  of  sulphate  of  baryta  =  30.36  p.  c.  of  sulphuric 
acid  in  the  anhydrous  salt. 

I.  0.3745  gm.  of  this  last  portion  of  sulphate  of  sar- 
cosine   (=  0.2608  gm.  after  deducting  the  sulphuric 
acid)  gave  0.3475  gm.  of  carbonic  acid. 

II.  0.3388  gm.  of  the  same  salt  (=  0.2389  gm.  after 


SULPHATE    OF    SARCOSINE.  61 

deducting  the* acid)  gave  0.3087  gm.  of  carbonic  acid, 
and  0.1735  gm.  of  water. 

III.  0.2674  gm.  of  sulphate  of  sarcosine  (=  0.1865 
gm.  after  deducting  the  acid)  gave  0.2475  gm.  of  car- 
bonic acid,  and  0.138  gm.  of  water. 

If  sulphate  of  sarcosine  be  analogous  in  composition 
to  the  sulphates  of  other  organic  bases,  the  anhydrous 
salt  contains  1  eq.  of  sarcosine  combined  with  1  eq.  of 
hydrated  sulphuric  acid,  and  therefore,  in  calculating 
the  analyses,  if  we  deduct  the  weight  of  anhydrous  sul- 
phuric acid  present,  we  must  obtain  in  the  remainder  a 
formula  which  includes  the  elements  of  sarcosine  -f-  1 
eq.  of  water. 

The  formula  C6  N  H7  O4  -f-  H  O  would  yield,  in  100  Formula  or 

_      .  sarcosine  in 

PartS,  the  sulphate. 

Theory.  Experiment. 

6  eqs.  Carbon  .  .  36  36.73  '36.34  1$569  36J28 
1  eq.  Nitrogen  .  14 

8  eqs.  Hydrogen  .  8  8.16  7.90*  8.16  8.25 
o  eqs.  Oxygen  .  40 

~98 

The  loss  sustained  by  the  crystallized  salt  at  212°  in- 
dicates the  presence  of  1  eq.  of  water  of  crystallization 
=  6.1  per  cent. 

The  Sulphate  of  Sarcosine,  when  heated  to  212°, 
consists  of 

Calculated.  Found. 


1  eq.  Sulphuric  acid          .    40  28.98  29.25        30.36  Formula  of 
1  eq.  Water                               9  >                                                         lhe  sulPhate- 

1  el  Sarcosine          .         .     89 1  71'02  70'75        ™'<* 

I  eq.  Sulphate  of  Sarcosine  138  100.00  100.00  100.00 

N  *  The  hydrogen  in  this  analysis  fell  below  the  truth,  which 
arose  from  the  circumstance,  that  the  salt  was  decomposed  by 
mixture  with  chromate  of  lead,  and  the  water  of  the  sulphuric 
acid  being  set  free,  a  portion  of  it  was  lost  in  the  process  of  ex- 
hausting the  tube  previous  to  the  combustion. 

6 


62  FORMATION    OF    SARCOSINE. 

I  regret  much  that  want  of  material  prevented  me 

from  multiplying  experiments  with  this  interesting  base  ; 

but  I  believe  that  no  doubt  can  be  entertained  as  to  its 

composition  and  its  atomic  weight. 

Formation  of      The  formula  above  given  for  sarcosine  explains  its 

sarcosine  ex-  ° 

plained.         production  from  kreatine  in  a  satisfactory  manner. 

If  from  the  elements  of  crystallized  kreatine  we  sub- 
tract those  of  sarcosine,  there  remains  a  formula  exact- 
ly identical  with  that  of  urea. 

Kreatine  con-  From  1  eq.  Kreatine  =  Cs  NS  Hn  O& 

tains  the  ele-  TA    j         •«          o  •  n    TVT    TT     s~\ 

ments  of  sar-  Deduct  1  eq.  Sarcosine  =  Ce  N   HT  04 
cosine  and  of 

urea.  There  remains  1  eq.  Urea  =  C2  N*  H4   Oa 

It  is  consequently  obvious,  that,  in  the  decomposition 
of  kreatine  by  baryta,  carbonic  acid  and  ammonia  are 
secondary  products  derived  from  the  decomposition  of 
urea.  I  have  ascertained  that  a  solution  of  urea  in  ba- 
rytic  water  is  resolved  by  long  boiling  into  carbonate  of 
baryta  and  ammonia  with  the  same  appearances  as 
Urea  is  form-  those  above  described  ;  and  I  have  also  ascertained  that 

ed  in  the  pro-  .  ..       .  ..,..,.. 

cess.  urea  is  present  in  the  liquid  when  kreatine  is  boiled  with 

baryta,  if  examined  before  the  whole  of  the  kreatine  is 
decomposed.  If  the  operation  be  arrested  when  the 
disengagement  of  ammonia  is  strongest,  the  free  baryta 
precipitated  by  carbonic  acid,  the  liquid  filtered  and 
evaporated  to  dryness,  and  nitric  acid  added  to  the  resi- 
due, there  is  obtained  a  crystalline  mass,  which,  when 
dried  in  blotting  paper  and  treated  with  alcohol,  yields 
to  that  solvent  nitrate  of  urea.  If  the  alcoholic  solution 
be  heated  with  oxide  of  lead,  nitrate  of  lead  is  precipi- 
tated, and  the  liquid  gives,  on  evaporation,  colorless 
prisms,  the  concentrated  aqueous  solution  of  which 
forms  with  oxalic  acid  a  crystalline  precipitate.  These 
prisms,  when  heated,  melt  easily,  give  off  ammonia, 
and  leave  a  white  residue,  which,  when  further  heated, 


arcosine  i 

isomeric 


INOSINIC    ACID.  63 

is  dissipated  in  the  form  of  the  vapor  of  hydrated  cy- 
anic acid. 

According  to  the  formula  established  by  the  preced-  Sar 

„  .  t  isomerc 

mg  analyses  for  sarcosine,  it  contains  the  same  ele-  with  lacta- 
ments,  and  in  the  same  relative  proportions,  as  the  lac-  with  um- 
tamide  of  Pelouze  and  the  urethane  of  Dumas.*     But 
the  insolubility  of  sarcosine  in  ether  and  alcohol  suffi- 
ciently distinguishes  it  from  these  two  compounds. 

Sarcosine  and  urea  are  not,  however,  the  only  prod-  Sarcosine  and 

-,.,  ..  -       ,  •  1  1  TP     Urea     n0t     tne 

ucts  of    the  decomposition  of    kreatine   by  baryta.     If  only  prod- 

water  be  added  to  the  alcohol  from  which  the  sulphate 

of  sarcosine  has  been  crystallized,  and  the  liquid  neu- 

tralized by  carbonate  of  baryta  be  filtered  and  evapo- 

rated to  the  consistence  of  a  thin  syrup,  there  are  de- 

posited, long  before  the  point  is  reached  at  which  sarco- 

sine would  crystallize,  long  colorless  prisms  or  scales, 

of  a  feeble  acid  reaction,  which  at  first,  for  this  reason, 

I  took  for  an  acid.     But  they  are  fusible  and  volatile, 

without  leaving  a  residue  of  baryta  ;  they  are  very  sol-  Another  sub- 

uble  in  water  and  alcohol,  and  also  in  30  parts  of  ether  ;  curs  ; 

the  aqueous  solution  causes  no  precipitate  in  nitrate  of 

silver,  corrosive  sublimate,  acetate  of  lead,  or  in  salts 

of  lime  and  baryta.     Unfortunately  I  did  not  obtain  a  possibly 

.     '  .  urethane. 

quantity  sufficient  for  an  analysis  of  this  substance,  so 
as  to  decide  whether  it  agrees  in  composition  with  ure- 
thane, which  it  much  resembles. 

Inosinic  Acid. 

When  the  liquid  from  flesh,  treated  as  formerly  de- 
scribed, has  entirely  deposited  the  crystals  of  kreatine, 
and  is  somewhat  further  concentrated  by  evaporation, 
if  alcohol  be  added  to  it  in  small  quantities  till  the  whole 
becomes  milky,  it  deposits,  when  allowed  to  rest  for 

*  See  note  on  p.  42. 


64 


INOSINIC    ACID. 


Its  purifica- 
tion. 


some  days,  yellowish  or  white  granular,  foliated  or  acic- 
ular  crystals,  which  may  be  separated  from  the  viscid 
mother  liquor,  although  slowly,  by  filtration,  and  may 
be  washed  with  alcohol. 

These  crystals  are  a  mixture  of  many  different  sub- 
stances, among  which  kreatine  is  invariably  found.  If 
the  whole  of  the  phosphoric  acid  has  not  previously 
been  removed  from  the  original  solution  of  flesh,  this 
deposit  contains  phosphate  of  magnesia ;  but  the  chief 
ingredient  is  the  potash  or  baryta  salt  of  a  new  acid,  to 
inosinic  acid,  which  I  shall  give  the  name  of  Inosinic  acid. 

If  the  quantity  of  baryta  added  has  been  exactly  suf- 
ficient to  precipitate  the  whole  of  the  phosphoric  acid, 
the  crystals  contain  inosinate  of  potash ;  and  finally,  if 
the  baryta  has  been  added  in  excess,  they  consist  of 
inosinate  of  baryta,  or  a  mixture  of  these  two  salts. 

To  purify  the  acid,  the  deposit  is  dissolved  in  hot  (not 
boiling)  water,  and  chloride  of  barium  is  added  to  the 
solution.  On  cooling,  crystals  of  inosinate  of  baryta 
are  deposited,  which,  by  a  recrystallizatiori,  are  ren- 
dered perfectly  pure. 

Inosinic  acid  is  easily  prepared  from  the  inosinate  of 
baryta,  by  the  cautious  addition  of  sulphuric  acid  to 
separate  the  baryta  ;  or  from  the  inosinate  of  copper, 
by  the  action  of  sulphuretted  hydrogen.  The  solution 
of  the  latter  salt,  after  being  decomposed  by  sulphuret- 
ted hydrogen,  is  generally  brown  and  turbid,  from  sus- 
pended sulphuret  of  copper,  but  it  is  rendered  colorless 
by  a  little  blood  charcoal  and  filtration. 

Prepared  by  either  process,  the  solution  of  the  ino- 
sinic acid  has  a  strong  acid  reaction,  and  possesses  an 
agreeable  taste  of  the  juice  of  meat.  When  evaporat- 
ed, it  yields  a  syrup,  which,  after  weeks,  exhibits  no 
signs  of  crystallization.  If  this  syrup  be  mixed  with 
alcohol,  the  thick,  viscid  fluid  is  changed  into  a  hard. 


Its  proper- 


INOSINATE    OF    BARYTA.  65 

firm,  pulverulent  mass,  of  which  alcohol  dissolves  only 
traces.  From  a  concentrated  aqueous  solution  the  acid 
is  precipitated  in  white  amorphous  flocculi.  It  is  insol- 
uble in  ether. 

The  quantity  of  this  acid  at  my  disposal  was  not  suf- 
cient  for  an  analysis  of  it ;  but  the  analysis  of  the  ba- 
ryta salt  is  sufficient  to  determine  the  composition  of 
the  acid. 

0.312  gm.  of  inosinate  of  baryta,   dried   at  212°,  Analysis  of 

inosinate  of 

yielded,  when  ignited  with  a  mixture  of  soda  and  lime,  baryta. 
0.565  gm.  of  the  double  chloride  of  platinum  and  am- 
monium =  11.370  p.  c.  of  nitrogen. 

The  combustion  of  the  inosinate  of  copper  yielded  a 
gaseous  mixture,  containing  for  137  vols.  of  nitrogen 
673  vols.  of  carbonic  acid.  This  indicates  that  ino- 
sinic  acid  contains,  for  1  eq.  of  nitrogen,  5  eqs.  of  car- 
bon.* 

0.4493  gm.  of  dried  inosinate  of  baryta  yielded 
0.2043  gm.  of  sulphate  of  baryta  =  30.07  p.  c.  of  ba- 
ryta. 

0.5430  gm.  of  dried  .inosinate  of  baryta  yielded 
0.2546  gm.  of  sulphate  of  baryta  =  30.75  p.  c.  of  ba- 
ryta. 

0.4248  gm.  of  the  same  salt,  burned  with  chromate 
of  lead,  yielded  0.381  gm.  of  carbonic  acid,  and  0.101 
gm.  of  water. 

0.4178  gm.,  burned  with  chromate  of  lead,  yielded 
0.380  gm.  of  carbonic  acid,  and  0.0975  gm.  of  water. 

Hence,  the  anhydrous  inosinate  of  baryta  contains 

N.  CO2 

*  The  2d  tube  yielded  49  235 

3d  "  45  245 

4th          «  42.5  193.5 


136.5          673.5 
N  :  C  O2  =  1  :  5. 
6* 


00  INOSINATES. 

Calculated.  Found. 

Formula  of     10  eqs.  Carbon         .        .         .60        23.96  24.46        24.80 

rtrouTlXt.         2  eqs.  Nitrogen  ...        28        11.18  11.37        11.37 

6  eqs.  Hydrogen    ...      6          2.40  2  64          2.59 

10  eqs.  Oxygen    ...        80        31.95  31.46        30.49 

1  eq.  Baryta  ....     76.4     30.51  30.07        30.75 

1  eq.  Inosinate  of  Baryta  .        250.4   100.00       100.00       100:00 
Formula  of         After  deducting  the  baryta,  the  anhydrous  acid  com- 

the  anhy-  .       .  .    .  J  J 

ikous  acid,      bined  with  it  contains 

10  eqs.  of  Carbon, 

2  eqs.  of  Nitrogen, 

6  eqs.  of  Hydrogen, 
10  eqs.  of  Oxygen  ; 

and  of  the      and  if  we  suppose  the  baryta  replaced  by  its  equivalent 

acid.  of  water,  the  formula  of  inosinic  acid  will  be  C10  N2  H7 

O^doNaHedo  +  HO. 

inosinates.  Inosinates.  —  Free  inosinic  acid  does  not  precipitate 
lime-water  or  barytic  water ;  but  when  these  mixtures 
are  left  to  evaporate  in  the  air,  there  are  formed  trans- 
parent pearly  scales  of  the  inosinates  of  lime  and  bary- 
ta. The  free  acid,  as  well  as  its  soluble  salts,  causes  a 
precipitate  in  acetate  of  copper;  the  inosinate  of  cop- 
per appears  as  a  fine  greenish-blue  precipitate,  which 
does  not  dissolve  even  in  boiling  water,  and  is  not 
blackened  by  it.  Salts  of  silver  are  precipitated  white 
by  inosinates ;  the  precipitate  is  gelatinous,  of  the  as- 
pect of  hydrate  of  alumina,  soluble  in  nitric  acid  and 
ammonia.  In  the  salts  of  lead  inosinic  acid  causes  a 
.  white  precipitate.  The  salts  of  inosinic  acid  with  the 
alkalies  are  decomposed  when  heated  on  the  platinum 
spatula,  and  give  out  a  strong  and  agreeable  smell  of 
roast  meat. 

inosinate  of  Inosinate  of  Potash.  — This  salt  is  obtained  from  the 
baryta  salt  by  cautious  precipitation  of  the  baryta  by 
carbonate  of  potash,  and  also  directly  from  the  juice  of 
flesh  (see  p.  64).  It  is  very  soluble  in  water,  and  crys- 


INOSINATES.  67 

tallizes  in  long,  slender,  four-sided  prisms.  It  is  insol- 
uble in  alcohol,  and  is  precipitated  by  it,  even  from  di- 
luted aqueous  solutions,  as  a  granular  powder.  The 
addition  of  alcohol  to  a  concentrated  solution  of  inosi- 
nate  of  potash  causes  it  to  become  semi-solid,  from  the 
deposition  of  fine  pearly  scales.  The  following  deter- 
mination of  the  amount  of  potash  was  made  with  a 
specimen  of  the  salt  prepared  directly  from  the  juice 
of  flesh  after  the  separation  of  kreatine.  The  salt  was 
dissolved  in  water,  precipitated  by  nitrate  of  silver,  the 
precipitate  well  washed,  and  the  potash  in  the  filtered 
liquor  determined  in  the  form  of  nitrate. 

0.4484  gm.  of  inosinate  of  potash  lost,  when  heated 
to  212°,  0.0987  gm.  of  water  =  22.02  p.  c. 

0.3495  gm.  of  the  anhydrous  salt  yielded  0.156  gm. 
of  nitrate  of  potash. 

The  calculated  composition  of  the  anhydrous  salt  in 
100  parts  is 

Found. 

1  eq.  Inosinic  acid         .         174  78.7          79.27  Formula  of 

leq.  Potash  .        .      47.2          21.3          20.73  SftJSSl. 

1  eq.  Inosinate  of  potash      221.2         100.0         100.00 

The  loss  of  weight  at  212°  indicates  the  presence  of 
7  eqs.  of  water  of  crystallization  =  22.5  per  cent. 

Inosinate  of  Soda.  —  This  salt  crystallizes  in  slender  inosinate  of 
needles,  of  silky  lustre,  and  is  extremely  soluble  in 
water,  but  insoluble  in  alcohol. 

Inosinate  of  Baryta.  —  This  salt  dissolves  sparingly  inosinate  of 
in  cold,  more  easily  in  hot  water,  and  is  insoluble  in     ryla' 
alcohol.     1000  parts  of  water  at  60°  dissolve  2.5  parts 
of  inosinate  of  baryta.     When  acted  on  by  hot  water, 
it  exhibits  a  peculiarity  similar  to  what  is  observed  in 
phosphosinate   of   baryta.     If  a  solution,  saturated  at 
from  140°  to  158°,  is  heated  to  boiling,  a  part  of  the 
salt  is  deposited  in  the  form  of  a  resinous  mass ;  again, 


68  INOSINATES. 

while  water  at  158°  dissolves  a  certain  amount  of  the 
salt,  the  same  quantity  of  boiling  water  always  leaves 
a  part  undissolved,  and  this  residue,  by  long  boiling, 
undergoes  a  change,  by  which  it  loses  its  solubility 
even  in  water  at  the  lower  temperature  above  men- 
tioned. 

The  crystals  of  inosinate  of  baryta  are  longish,  four- 
sided  scales  of  pearly  lustre,  which,  when  dry,  have 
the  aspect  of  polished  silver.  At  212°  the  crystals 
lose  water,  becoming  dull  and  opaque ;  in  dry  air  they 
readily  effloresce. 

0.555  gm.  of  the  crystallized  salt  lost,  when  heated 
to  212°,  0.1059  gm.  of  water. 

1.060  gm.  lost,  at  212°,  0.2020  gm.  of  water. 

This  gives  for  100  parts  of  salt  19.07  of  water.  If 
the  inosinate  of  baryta,  like  the  inosinate  of  potash, 
contained  7  eqs.  of  water,  it  would  have  lost  20  p.  c. 
of  water. 

Tnosinateof  Inosinate  of  Copper.  —  This  salt,  when  dried,  forms 
a  light  blue  amorphous  powder.  It  is,  in  the  common 
sense  of  the  term,  insoluble  in  water,  which  only  dis- 
solves so  much  of  it,  that  ferrocyanide  of  potassium 
causes  a  faint  redness,  such  as  salts  of  copper  exhibit 
when  diluted  with  500,000  parts  of  water.  It  is  insol- 
uble in  acetic  acid,  easily  soluble  with  a  blue  color  in 
ammonia. 

inosinate  of  Inosinate  of  Silver.  —  The  gelatinous  precipitate, 
formed  by  soluble  inosinates  in  salts  of  silver,  is  some- 
what soluble  in  pure  water,  but  less  so  in  water  con- 
taining nitrate  of  silver.  It  is  not  blackened  by  light, 
or  only  to  a  very  trifling  extent. 

The  inosinate  of  silver  obtained  in  the  analysis  of  the 
potash  salt  (see  p.  67)  was  decomposed  by  hydrosul- 
phuric  acid,  and  the  sulphide  of  silver  thus  obtained 
converted  into  chloride  of  silver. 


INOSINIC    ACID.  69 

0.3495  gm.  of  the  anhydrous  inosinate  of  potash 
yielded,  in  this  way,  0.216  gm.  of  chloride  of  silver, 
corresponding  to  49.99  parts  of  oxide  of  silver,  from 
100  parts  of  the  potash  salt. 

If  the  inosinate  of  silver  be  proportional  in  composi- 
tion to  the  inosinate  of  potash,  100  parts  of  the  latter 
salt  ought  to  yield  51.02  parts  of  oxide  of  silver.  The 
experiment  gave,  as  we  have  seen,  50  parts  of  oxide  of 
silver. 

This  difference  is  considerable ;  but  when  so  many 
operations  must  be  performed  with  one  and  the  same 
portion  of  substance,  errors  of  this  kind  are  unavoid- 
able. I  am  quite  aware  how  imperfect  is  the  investi- 
gation of  inosinic  acid,  and  of  its  salts,  which  I  have 
been  able  to  make  ;  but  flesh  contains  only  a  very 
small  quantity  of  this  substance  ;  and  of  that  which  I 
obtained,  a  great  part  was  necessarily  consumed  in  as- 
certaining its  nature  and  properties. 

Inosinic  acid  appears,  from  its  composition,  to  belong  inosinic  acid 
to  the  coupled  acids.     Considered  as  hydrate,  it  con-  coupled  acid 
tains   the   elements   of  acetic  'acid,  oxalic   acid,  and 
urea :  — 

1  eq.  anhydrous  Acetic  acid         .         .         €4         HS  Os 

2  eqs.  anhydrous  Oxalic  acid  .     C4  Oe 
1  eq.  Urea  •         •         •         .         .         •         C2   N2  H4  O2 

1  eq.  hydrated  Inosinic  acid  .  .  .  Cio  Na  H7  Ou 
When  the  acid  is  heated  with  hyperoxide  of  lead, 
with  the  addition  of  diluted  sulphuric  acid,  the  oxide 
loses  its  brown  color  and  becomes  white,  and  the  fil- 
tered liquid,  when  deprived  of  the  excess  of  sulphuric 
acid,  deposits  on  evaporation  needle-shaped  crystals. 
When  mixed,  in  the  concentrated  state,  with  nitric  acid, 
no  precipitate  occurs,  but  there  are  obtained  by  evapo- 
ration small  colorless  granular  crystals,  which  I  could 
not  further  examine,  on  account  of  the  smallness  of  the 


70 


KKEATININE    IN    MUSCLE. 


quantity  of  inosinic  acid  which  I  was  able  to  devote  to 
this  experiment. 
Effect  of  The  temperature  at  which  the  solution  of  the  iuice 

temperature 

on  the  prep-  of    flesh  is  evaporated  has  a  great  influence  on    the 

aration  of  f 

inosinates      preparation  of  the  salts  of  inosinic  acid.     In  many  m- 

from  the  * 

juice  of  flesh,  stances,  when  the  temperature  had  never  exceeded 
212°,  I  have  obtained  no  trace  of  inosinate  of  potash 
or  baryta  ;  while  fluid,  derived  from  the  flesh  of  the 
same  animal,  yielded  tolerably  large  quantities,  when 
during  the  evaporation  a  strong  current  of  air  was 
made  to  pass  over  the  surface  of  the  liquid,  by  which 
means  its  temperature  was  kept  as  low  as  from  122° 
to  140°. 

Kreatinine,  as  a  Constituent  of  Muscle. 

exTs^s'TrTthe  When  the  juice  of  flesh,  from  which  the  inosinates 
juice  of  flesh,  have  been  precipitated  by  alcohol,  is  mixed  with  an 
additional  quantity  of  alcohol,  it  separates,  after  about 
five  times  its  volume  of  alcohol  have  been  added,  into 
two  layers,  of  which  one,  a  thick,  syrupy,  of  a  brown- 
ish-yellow color,  amounting  to  ^th  of  the  bulk  of  the 
other,  falls  to  the  bottom  of  the  vessel.  If  these 
liquids  are  mixed  by  agitation,  they  again  separate  on 
standing. 

its  extrac-  In  the  heavy  viscid  portion,  at  a  temperature  of  23°, 
there  are  soon  formed  a  number  of  transparent  color- 
less four-sided  prisms,  which  are  pure  chloride  of  po- 
tassium. They  melt  when  heated,  without  blackening ; 
their  aqueous  solution  precipitated  nitrate  of  silver, 
and  gave,  with  bichloride  of  platinum,  a  yellow  pre- 
cipitate ;  while  the  mother  liquid,  when  mixed  with 
alcohol,  contained  no  traces  of  the  double  chloride  of 
platinum  and  sodium. 

If  the  lighter  fluid  be  poured  off  from  the  heavy  vis- 
cid one,  and  the  latter  mixed  with  its  own  volume  of 


KREATININE    IN    THE   ANIMAL    ORGANISM.  71 

ordinary  ether,  it  becomes  milky,  and  on  standing,  a 
new  separation  takes  place. 

On  the  bottom  of  the  vessel  there  collects  an  amber- 
yellow  viscid  liquid,  from  which  the  supernatant  lighter 
ethereal  liquid  can  be  easily  separated  by  decantation. 
The  heavier  consists  almost  entirely  of  lactate  of  pot- 
ash ;  the  lighter  contains  also  a  certain  quantity  of  that 
salt,  but  the  chief  ingredient  of  it  is  an  organic  base, 
which  in  properties  and  composition  has  been  found  to 
be  identical  with  kreatinine. 

When  the  ether  and  alcohol  are  distilled  off  from 
this  lighter  fluid,  and  the  residue  evaporated  to  the  con- 
sistence of  a  thin  syrup,  it  forms,  on  cooling,  a  semi- 
solid  mass  of  slender  foliated  crystals,  which,  by  the 
addition  of  alcohol,  may  be  separated  from  the  mother 
liquid.  When  these  crystals  are  washed  with  a  little 
alcohol,  dried,  and  dissolved  in  boiling  alcohol,  the  so- 
lution deposits,  on  cooling,  crystals  possessing  the  form 
and  properties  of  kreatine.  At  212°  they  become 
opaque  and  dull,  and  lose  twelve  per  cent,  of  water. 
The  mother  liquid,  by  gentle  evaporation,  yields  yel- 
lowish four-sided  tables.  By  means  of  a  little  blood- 
charcoal  and  hydrated  oxide  of  lead,  they  are  easily 
rendered  colorless  ;  their  aqueous  solution  is  strongly 
alkaline,  and  causes  white  crystalline  precipitates  in 
solutions  of  nitrate  of  silver,  corrosive  sublimate,  and 
chloride  of  zinc.  When  mixed  with  hydrochloric  acid 
and  bichloride  of  platinum,  yellow  crystals  are  ob- 
tained, of  the  form  and  properties  of  the  double  chlo- 
ride of  platinum  and  kreatinine. 

Of  this  platinum  salt,  3.3728  gm.  yielded  on  igni- 
tion 0.1153  gm.  of  platinum  =  30.92  p.  c.  This  is 
the  same  percentage  of  platinum  as  in  the  double 
chloride  of  platinum  and  kreatinine. 

A   portion  of  the  same  salt,  burned  with  oxide  of 


72  KREATININE    IN    THE    ANIMAL    ORGANISM. 

copper,  yielded  a  gaseous   mixture,  containing  for  3 
volumes  of  nitrogen  8  volumes  of  carbonic  acid.* 

This  is  the  same  proportion  as  in  kreatinine. 
Analysis  of        0.1513  gm.  of  the  dried  crystals  of  kreatinine,  pre- 
from  the        pared  directly  from  flesh,  yielded  0.2316  gm.  of  car- 

juiceof  flesh.  .  .  j           j  /\ /\o/-»r  /» 

home  acid,  and  0.0865  gm.  of  water. 

Hence  this  substance  contains,  in  100  parts, 

Kreatinine  Kreatinine 

from  Flesh.  from  Kreatine. 

Carbon          .         .         .        41.7  42.54 

Nitrogen           ..."  " 

Hydrogen     .         .         .          6.23  6.38 
Oxygen                                        " 

These  results  leave  no  doubt  as  to  the  nature  of  this 
substance,  and  the  occurrence  of  kreatinine  in  the  or- 
ganism. The  objection,  that  the  kreatinine  might  have 
been  formed  by  the  action  of  the  free  acid  in  the  juice 
of  flesh  on  the  kreatine,  during  the  short  heating  neces- 
sary to  coagulate  the  albumen,  is  at  once  destroyed  by 
the  occurrence  of  kreatinine  in  neutralized  urine,  and 
also  by  the  fact,  that  kreatine  may  be  dissolved  and 
boiled  for  a  long  time  in  mineral  acids  of  much  greater 
concentration  than  the  acid  of  the  juice  of  flesh  pos- 
sesses, without  suffering  the  slightest  change, 
simple  pro-  Now  that  the  nature  of  this  substance,  which  I  at 
tractingknja-  firgt  took  for  a  peculiar  base,  different  from  kreatine,  is 
flesh.6  r  known,  it  is  no  longer  necessary  to  employ  the  circu- 
itous methods  which  I  was  compelled  to  adopt,  in  order 
to  prevent  all  foreign  chemical  action  during  its  prep- 


N. 
*  The  2d  tube  yielded  60 
3d           «            66 
4th         «            79 

CO2. 

156 
176 
211 

205 
N  :  C==3:8. 

543 

LACTIC  ACID  IN  THE  JUICE  OF  FLESH.      73 

aration.  When  the  mother  liquid  which  has  deposited 
the  inosinates  is  evaporated  to  dryness  in  the  water- 
bath,  and  boiled  with  alcohol,  all  the  kreatinine  is  dis- 
solved, and  when  chloride  of  zinc  is  added  to  the  solu- 
tion, Pettenkofer's  compound  is  deposited,  either  at  once 
or  after  some  hours,  as  a  crystalline  deposit,  from 
which,  when  acted  on  by  hydrated  oxide  of  lead,  pure 
kreatinine  is  easily  obtained. 

Lactic  Acid. 

When  the  liquid  from  which  the  inosinates  have  Lactic  acid 
been  deposited  is  evaporated  in  the  water-bath,  and  the  ent  of  feefe. 
residue  acted  on  by  alcohol,  all  the  lactates  are  dis- 
solved. If  the  alcoholic  solution  be  separated  from  the 
syrupy  viscid  liquid  which  is  insoluble  in  it,  and  the 
alcohol  distilled  off,  there  is  left  a  yellow  syrup,  which, 
in  the  course  of  8  or  10  days,  forms  a  soft,  semi-solid 
crystalline  mass.  The  crystals  which  form  in  it  con- 
sist of  kreatine,  and  of  the  potash  salt  of  a  riitrogen- 
ized  acid,  differing  in  properties  from  inosinic  acid  ; 
they  are  contained  in  the  mother  liquid,  the  chief  ingre- 
dient of  which  is  uncrystallizable  lactate  of  potash. 

To  prepare  lactic  acid  from  this  mass,  it  is  mixed  Preparation 
with  its  own  volume  of  diluted  sulphuric  acid  (made 
with  1  vol.  of  oil  of  vitriol  and  2  vol.  of  water),  or 
with  a  solution  of  oxalic  acid  of  equal  strength.  Of 
the  latter,  so  much  is  added  as  to  produce  a  crystalline 
deposit,  and,  in  either  case,  3  or  4  times  its  bulk  of 
alcohol  is  added  to  the  mixture. 

By  the  addition  of  alcohol,  the  sulphate  or  oxalate  of  an(j  puriiica- 
potash  is  precipitated,  while  the  lactic  acid  remains  in  iactic°acide 
solution.     This  solution  is  mixed  with  ether  till  no  fur- 
ther turbidity  is  produced,  the  liquid  is  filtered  from  the 
deposit,  the  ether  and  alcohol  are  distilled  off,  and  the 
residue  is  concentrated  in  the  water-bath  to  the  con- 
7 


74  LACTATES    OCCUR 

sistence  of  syrup.  This  syrup  is  again  acted  on  by  a 
mixture  of  alcohol  and  ether,  half  its  volume  of  alco- 
hol being  first  added,  and  then  5  times  its  volume  of 
ether,  by  which  means  a  nearly  pure  solution  of  lactic 
acid  in  ether  is  obtained.  The  ether  is  then  distilled 
off,  and  the  residue  mixed  with  milk  of  lime,  till  it  ac- 
quires a  strong  alkaline  reaction.  The  liquid  is  filtered,, 
and  the  solution  of  lactate  of  lime  is  left  in  a  warm 
place,  where  it  soon  forms  a  mass  of  crystals,  which 
are  in  themselves  colorless,  but  appear  yellow  from  the 
adhering  mother  liquor.  The  mass  is  diluted  with  al- 
cohol, and  thrown  on  a  filter,  where  it  is  washed  by 
cautiously  adding  cold  alcohol  so  as  to  displace  the 
mother  liquor,  till  the  crystals  appear  quite  white.  In 
order  to  separate  any  gypsum  that  may  be  present, 
they  are  now  dissolved  in  alcohol  of  60  per  cent.,  the 
solution  is  filtered,  treated,  if  colored,  with  blood-char- 
coal, and  evaporated,  when  it  readily  yields  perfectly 
pure  lactate  of  lime.  * 

Modification  From  every  sort  of  flesh,  except  that  of  fishes,  lac- 
cesshfo?fish.  tate  of  lime  may  be  obtained  by  this  process ;  but  for 
fish  it  is  necessary  to  modify  it.  The  liquid,  for  exam- 
ple, obtained  from  the  flesh  of  the  pike,  is  evaporated 
to  a  syrup,  and  mixed  with  an  aqueous  solution  of  tan- 
nic  acid,  which  causes  a  thick  yellowish- white  precip- 
itate, softening  like  pitch  when  heated.  The  filtered 
liquid  is  concentrated,  and  treated  as  above  directed 
with  sulphuric  or  oxalic  acid,  and  at  last  there  is  ob- 
tained, in  the  ethereal  solution,  a  mixture  of  gallic  acid 
(formed  by  the  oxidation  of  tannic  acid)  and  lactic 
acid,  from  which,  when  the  alcohol  is  expelled,  the  gal- 
lic acid  partly  crystallizes.  Without  separating  these 
crystals,  the  acid  mixture  is  saturated  with  milk  of  lime, 
the  solution  is  filtered  from  the  dark  brown  (nearly 
black)  residue,  treated  with  blood-charcoal,  and  con- 


IN    THE    JUICE    OF    FLESH.  75 

centrated,  when  after  a  time  it  yields  snow-white  crys- 
tals of  lactate  of  lime. 

When  the  lime  is  precipitated  from  the  solution  of 
the  pure  lactate  by  sulphuric  acid,  the  filtered  liquid 
evaporated  in  the  water-bath,  and  the  residue  acted  on 
by  ether,  pure  lactic  acid  is  dissolved,  and  from  this 
any  other  lactate  may  be  easily  prepared. 

1.276  gm.  of  lactate  of  lime  lost,  when  heated  to  Analysis  of 

the  lactates 

212°,  0.323  em.  of  water  =  25.3  per  cent.  prepared 

from  flesh. 

1.4735  gm.  of  lactate  of  lime  lost,  when  heated  to 
212°,  0.3805  gm.  of  water  =  25.8  per  cent 

Gm.  Gm.  p.  c.  of  lime. 

0.4900  of  lactate  of  lime  (fowl)  yielded  0.2195  of  carbonate  of  lime  =  25.53     LaCtate  of 
0.4870  "  (horse)      "      0.2245  '«  =25.84     lime. 

0.5377  «  (fox)          «'      0.2452  "  =25.54 

0.1805  "  (pike)       «'      0.0830  *'  =25.74 


Mean  proportion  of  lime  in  100  parts  of  the  salt  =  25.65 

Hence,  lactate  of  lime  contains,  in  100  parts, 


Calculated.  Found. 


1  eq.  Lactic  acid  81  74.32  7447  74.19  74.46  74^26  Jh™nhJ-°f 
1  eq.  Lime  28  25.68  25.53  25.81  25.54  25.74  drous 

leq.  Lactate  of  lime  109    100.00    100.00    100.00    100.00    KXMX) 

The  crystallized  lactate  of  lime  contains 

Calculated.  Found. 

1  eq.  Lactate  of  lime  .  .  109  75.18  74.7  74J2  and  of  the 
4  eqs.  Water  ....  36  24.82  25.3  25.8  'J**®** 
I  eq.  crystallized  Lactate  of  lime  145  100.00  100.0  100.0 

0.274  gm.  of  anhydrous  lactate  of  lime  (ox)  yielded 
by  combustion  with  chromate  of  lead  0.3335  gm.  of 
carbonic  acid,  and  0.1152  gm.  of  water. 

0.6420  gm.  of  anhydrous  lactate  of  lime  (fox) 
yielded  0.7660  gm.  of  carbonic  acid,  and  0.274  gm.  of 
water. 


0  ANALYSIS    OF    THE    LACTATES 

The  anhydrous  lactate  of  lime  therefore  contains 

Calculated.  Found. 


Composition    6  eqs.  Carbon        ...         36        33.02        33.11         32.54 
oflactateof    5  eqs.  Hydrogen       ...       5  4.59  4.66  4.70 

5  eqs.  Oxygen  ...  40  36.71  36.58  37.11 
1  eq.  Lime  ....  28  25.68  25.65  25.65 
leq.  anhydrous  Lactate  of  lime  109  100.00  100.00  100.00 

oflactateof       The  lactate  of  zinc,  prepared  from  flesh,  was  also 

zinc.  *          i 

analyzed. 

Gm.  Gm.  p.  c. 

0.499  of  lactate  of  zinc,  when  heated  to  212°,  lost  0.068  of  water  =  13.6 
1.3295  "  •'  0.1775        "       =13.3 

Mean  loss      .        .        .        .        13.45 

0.564  gm.  of  crystallized  lactate  of  zinc  left,  when 
ignited,  0.1645  gm.  of  oxide  of  zinc  =  29.16  per 
cent. 

0.3153  gm.  of  anhydrous  lactate  of  zinc  left,  when 
ignited,  0.1052  gm.  of  oxide  of  zinc  =  33.31  per 
cent. 

0.5690  gm.  of  the  anhydrous  lactate  yielded,  by 
combustion,  0.6125  gm.  of  carbonic  acid,  and  0.213 
gm.  of  water. 

0.2260  gm.   of   the  anhydrous   lactate   yielded,  by 
combustion,  0.244  gm.  of  carbonic  acid,  and  0.0838 
gm.  of  water. 
Us  formula         Hence,  the  crystallized  lactate  of  zinc  contains  * 

in  the  crys- 

lale  5  Calculated.  Found. 

1  eq.  Lactic  acid      ...        81                 58.07  57.44 

1  eq.  Oxide  of  zinc     .        .        .     40.5              29.03  29 16 

2  eqs.  Water            .        .         .         18  -  1290  13.40 
1  eq.  crystallized  Lactate  of  zinc  139.5  100.00  100.00 


*  According  to  the  investigations  of  Engelhard  and  Maddrell, 
lactate  of  lime,  prepared  by  Fremy's  process,  contains  5  eqs. 
(=  29  p.  c.)  and  the  lactate  of  zinc  3  eqs.  (=  18  p.  c.)  of  water 
of  crystallization.  It  is  possible  that  this  variation  in  the 


PREPARED    FROM    FLESH.  77 

The    ultimate  analysis  of  the  anhydrous  lactate  of  in  the  an- 
hydrous 
zinc  gives  state. 

6  eqs.  Carbon          ...      36       29.63  29.35        29.44 

5  eqs.  Hydrogen          .         .            5         4.11  4.16          4.12 

5  eqs.  Oxygen          ...      40       32,93  33.18        33.13 

1  eq.  Oxide  of  zinc    .        .          40.5    33.33  33.31  ___  33.31 

1  eq.  anhydrous  Lactate  of  zinc  121.5  100.00  100.00       100.00 

From   the   preceding  analysis  it  evidently   appears  The  non- 
that  the  non-nitrogenized  acid  occurring  in  the  animal  acid  of  flesh 

•1-1         •  i       i  •  i    /.  j     •  MI     is  lactic 

organism   is   identical   with   the  acid  formed   in   milk  acid, 
when  it  becomes  sour,  and  into  which  sugar  of  milk, 
starch,  grape  sugar,  and  cane  sugar  are  converted  by 
contact  with  animal  substances  in  a  state  of  decompo- 
sition.* 

The  Inorganic  Constituents  of  the  Juices  of  Flesh. 
Chevreul  has  already  directed  attention  to  the  very  inorganic 

J   .  •        i    •        i       constituents 

large  quantity  of  inorganic  substances  contained  in  the  of  the  juice 
juice  of  beef.     In  his  experiments  they  amounted  to 
rather  more  than  a  fourth  part  of  the   weight  of  the 
matters  dissolved  in  the  soup  when  the  flesh  is  boiled 
with  water.     Of  the   saline  mass   which  he  obtained 
by   drying   up   and  incinerating  the   solution,   81   per 
cent,  were  found  soluble  in  water,  and  the  insoluble       __ 
residue  of  19   per   cent,   consisted   of  5.77  of  phos- 
phate of  lime  and  13.23  of  magnesia. 

It   is  evident  that  alkalic  salts  are   the  preponder-  Aikaiic 

i  salts  prepon- 

atmg  inorganic  constituents  of  the  juice  of  flesh,  and  derate  in  it. 


amount  of  water  in  these  two  salts  depends  on  this,  that  the 
lactates  from  flesh  were  crystallized  by  slow  evaporation,  and 
not  by  cooling. 

*  From  the  most  recent  researches  of  Engelhard  and  Mad- 
drell,  lactic  acid  appears  to  be  a  bibasic  acid.  It  forms  an 
acid  salt  with  baryta,  and  its  formula  must  consequently  be 
doubled. 

7* 


78 


INORGANIC    CONSTITUENTS 


Importance 
of  the  inor- 
ganic constit 
uonts. 


The  ash  of 
the  juice  of 
meat  con- 
tains only 
alkalic 
phosphates 
and  chlo- 
rides. 


that  phosphate  of  lime  is  in   the  smallest  proportion 
compared  to  those  salts  and  to  the  magnesia. 

Now,  since  we  may  assume  with  a  degree  of  prob- 
ability almost  amounting  to  certainty,  that,  in  so  per- 
fect a  machine  as  the  animal  organism,  every  part 
has  its  significance,  I  have  thought  it  of  importance 
to  make  some  experiments  on  the  nature  of  the  miner- 
al acids  and  alkalic  bases  occurring  in  the  juice  of 
flesh,  and  their  mutual  relations,  —  experiments  which, 
however  imperfect,  may  still  serve  as  points  of  de- 
parture for  future  researches. 

The  organized  constituents  of  the  body  have  been 
derived  from  unorganized  matters,  and  return  to  the 
unorganized  state  ;  and  it  is  especially  with  the  unor- 
ganized substances  that  our  researches  must  begin. 
If  now  it  can  be  demonstrated  by  investigation  that 
certain  inorganic  constituents  occur  in  the  flesh  of  all 
animals,  and  are  never  absent  therefrom,  it  will  follow 
that  they  are  essential  to  the  function  of  the  muscles, 
those  most  complex  parts  of  the  organism ;  while,  on 
the  other  hand,  a  variation  in  their  relative  proportions 
enables  us  to  infer  a  corresponding  variation  in  some 
vital  action. 

When  the  juice  of  flesh  (extracted  as  formerly  de- 
scribed, and  therefore  diluted  with  water)  is  evaporat- 
ed, even  without  the  addition  of  baryta,  it  acquires  at 
last,  even  when  the  temperature  never  exceeds  112°, 
a  brown  color,  and  a  taste  of  roast  meat,  and  leaves 
when  ignited  an  ash,  which  may  be  burned  white,  al- 
though with  some  difficulty.  This  ash  dissolves  almost 
entirely  in  water,  and  in  this  solution  acids  occasion 
no  effervescence ;  the  ash,  therefore,  contains  no  alka- 
line carbonates.  A  more  minute  examination  shows 
that  it  consists  only  of  alkaline  phosphates  and  chlo- 
rides. 


OF    THE    JUICE    OF    FLESH.  79 

The  precipitate  formed  by  baryta  in  the  juice  of  flesh  NO  sulphates 
in  many  cases  dissolves  entirely  in  diluted  nitric  acid ; 
and  in  those  cases  in  which  a  residue  of  sulphate  of 
baryta  is  left,  its  quantity  is  so. trifling,  that,  for  ex- 
ample, in  the  entire  flesh  of  a  fowl  or  of  a  fox  its 
weight  cannot  be  ascertained.  Sulphates  or  sulphu- 
ric acid  are  therefore  not  present  in  the  juice  of  flesh, 
a  fact  already  ascertained  by  Berzelius. 

The  soluble  salts  obtained  from  the  ash  of  the  juice  The  different 
of  flesh  contain   the  different   modifications   of  phos-  p^phoric 
phoric    acid,    which   are  easily  distinguished  by  their  aci  ' 
action  on  nitrate  of  silver. 

It  is  well  known  that  common  or  tribasic  phospho- 
ric acid  forms  three  different  salts  with  the  alkalies ; 
two  of  these,  in  their  aqueous  solution,  have  an  alka- 
line, the  third  has  an  acid,  reaction. 

When  a  salt  of  phosphoric  acid   with   3   atoms  of  characters 
fixed  base,  which  is  strongly  alkaline,  is  mixed  with  ent  forms  of 
neutral  nitrate  of  silver,  a  yellow  precipitate  is  formed,  phosphates, 
the  alkaline  reaction  disappears,  and  the  mixture,  after 
precipitation,  if  a  slight  excess  of  the  nitrate  of  silver 
be  present,  is  perfectly  neutral  to  test-paper. 

The  salts  of  tribasic  phosphoric  acid  with  2  atoms  of 
fixed  base  have  also  an  alkaline  reaction.  They  give 
with  neutral  nitrate  of  silver  the  same  yellow  precipi- 
tate, and  the  mixture,  after  precipitation,  is  neither 
alkaline  nor  neutral,  but  acid. 

When  these  latter  salts  are  ignited,  they  are  con- 
verted into  pyrophosphates  (bibasic  phosphates),  which, 
when  dissolved  in  water,  exhibit  an  alkaline  reaction, 
and  give  with  neutral  nitrate  of  silver  a  white  pre- 
cipitate. After  precipitation,  the  mixture  is  neutral. 

The  salts  of  tribasic  phosphoric  acid  with  1  atom 
of  fixed  base  have  a  strong  acid  reaction.  With  neu- 
tral nitrate  of  silver  they  give  the  yellow  precipitate 


80  CHARACTERS    OF    THE    DIFFERENT 

formerly  mentioned,  while  the  mixture  retains  its  acid 
reaction.* 

When  ignited,  these  latter  salts  pass  into  metaphos- 
phates  (monobasic  phosphates),  of  which  the  meta- 
phosphate  of  potash  is  not  soluble  in  water.  Meta- 

*  The  following  formulae  will  serve  to  elucidate  the  above  re- 
actions. 

3  Meo,  P  Os   is  the  neutral  tribasic  phosphate. 

The  atoms  of  base  may  be  all  of  metallic  oxide,  as 

(a)  3  Ca  O,  P  O5  3  Mg  O,  P  O5)  or  3  Na  O,  P  O5,  or  two  of 
metallic  oxide  and  one  of  water  or  ammonia, 

(6)  2  Na  O,  H  O,  P  O5,  or  2  Mg  O,  N  H  O4,  P  Os,  or  one 
of  fixed  base,  one  of  ammonia,  and  one  of  water,  as 

(c)  Na  O,  N  H4  O,  H  O,  P  O5. 

If  (a)  be  ignited,  it  remains  unchanged. 

If  (b)  be  ignited,  the  water  or  ammonia  is  driven  out,  and 

2  Na  O,  P  O5)  or  2  Mg  O,  P  O5)  the  bibasic  phosphate  or  pyro- 
phosphate,  remains. 

If  (c)  be  ignited,  both  ammonia  and  water  are  driven  out, 
and  the  Na  O,  P  Os(  metaphosphate  or  monobasic  phosphate, 
remains. 

(a)  gives  a  strong  alkaline  reaction,  a  yellow  precipitate  with 
nitrate  of  silver,  and  a  neutral  filtrate. 

3  Ca  O,  P  Os  -f  3  [AgO,  N  O5]  =  3  AgO,  P  Os  -f-  3  [Ca  O, 

N05]. 

(b)  gives  an  alkaline  reaction,  a  yellow  precipitate  with  ni- 
trate of  silver,  and  an  acid  filtrate. 

2  Na  O,  H  O,  P  O5  -f-  3  [Ag  O,  £  O5]  =  3  Ag  O,  P  Os  -f 

2  [Na  O,  N  Os]  +  H  O,  N  Os 

After  ignition  the  reaction  is  alkaline,  the  precipitate  with  nitrate 
of  silver  white,  and  the  filtrate  reacts  neutral. 
2  Na  O,  P  Os  +  2  [Ag  O,  N  O5]  =  2  Ag  O  —  P  Os  -f-  2  [Na  O, 
N05.] 

(c)  gives  an  acid  reaction,  a  yellow  precipitate  with  nitrate  of 
silver,  and  an  acid  filtrate. 

Na  O,  N  H4  O,  H  O,  P  Os  +  3  [Ag  O,  N  O5]  =  3  Ag  O,  P  Os  + 

Na  O,  N  Os  +  N  H4  O,  N  Os  -f-  H  O,  N  Os. 

After  ignition,  the  salt  gives  a  white  precipitate  with  silver  salt. 

Na  O,  P  0$  +  Ag  O,  N  Os  =  Ag  O,  P  Os  +  Na  O,  N  Os. 

—  E.  N.  H. 


MODIFICATIONS    OF    PHOSPHATES.  81 

phosphate  of  soda  dissolves  readily  in  water,  and  gives 
with  nitrate  of  silver  a  white  precipitate,  which  again 
dissolves  in  an  excess  of  the  precipitant. 

If  we  compare   with  the    characters  just  described  Characters 
those  of  the  ash  of  the  juice  of  flesh,  we  observe  the  of  the  juice 
following  facts.     The  ashes   of  the  juice  of  flesh,  in 
the  case   of  the   ox,    horse,    fox,   arid   roe-deer,    give 
with  water  a  strongly  alkaline  solution,  which  is  pre- 
cipitated, first  white,  then  yellow,  by  neutral  nitrate 
of  silver ;  and  the  mixture,  after  complete  precipitation, 
is  perfectly  neutral.     This  proves  that  the  ashes  con-  they  contain 

.  .  pyrophos- 

tain  salts  of  phosphoric  acid,  with  2  atoms  (pyrophos-  phatesand 

vrv  tribasic  phos- 

phates),  and    with    3   atoms    (tribasic    phosphates)    of  phates. 

fixed  alkaline  base. 

If  these  ashes  are  mixed  with  nitric  acid,  dried  up, 
and  again  ignited,  by  which  means  the  chlorine  of  the 
alkaline  chlorides  is  expelled,  and  the  metals  added 
to  the  phosphates  in  the  form  of  oxides,  the  propor- 
tion between  the  white  and  the  yellow  precipitate  with 
nitrate  of  silver  is  altered,  the  quantity  of  the  yellow 
precipitate  being  increased ;  but  the  two  colors  of  the 
precipitate  are  constantly  observed. 

The  ashes  of  the  juice   of  the   flesh  of  fowl  give  a  The  ashes  of 

T/T.  rrn   '  •  •    •  •     the  juice  of 

different  result.      1  he  aqueous  solution  precipitates  m-  fowl  con- 
trate  of  silver  purely  white ;  the  ashes,  therefore,  con- 
tain alkalic  pyrophosphates ;  and  when  they  are  acted 
on  by  nitric  acid  and  again  ignited,  the  soluble  portion 
still  precipitates  nitrate  of  silver  only  white,  although 
an  additional  quantity  of  alkali  is  thus  added  to  the 
phosphate   originally  present.      From   this   it   follows,  tainpyro- 
that  the  juice  of  the  flesh  of  fowl  must  contain  a  cer-  ESd^meu? 
tain  though    small  quantity  of  alkalic  phosphate  with  p 
1   atom   of  fixed  base   (metaphosphate),  since,  other- 
wise, after  the  action   of  nitric  acid  on  the  ashes,  a 
certain  quantity  of  phosphate  with  3  atoms  of  fixed 


82  ACIDS    AND    ALKALIES 

base  (tribasic  phosphate)  must  have  been  produced,  and 
thereby  a  yellow  precipitate  must  have  been  formed, 
to  a  corresponding  extent,  in  the  nitrate  of  silver. 
Proportion  of  The  whole  amount  of  alkalies,  therefore,  present  in 
the  phospho-  the  juice  of  the  flesh  of  the  ox,  horse,  fox,  and  roe- 
deer,  is  not  sufficient  to  convert  the  phosphoric  acid 
of  the  juice  entirely  into  the  so-called  neutral  salt,  that 
is,  the  salt  with  3  atoms  of  fixed  base.  In  the  fowl, 
the  whole  of  the  alkali  is  not  even  sufficient  to  convert 
the  phosphoric  acid  entirely  into  the  salt  with  2  atoms 
of  fixed  base. 

I  have  mentioned  in  a  preceding  part  of  this  me- 
moir, that  the  juice  of  flesh,  even  before  all  the  phos- 
phoric acid  has  been  precipitated  by  baryta,  at  a  pe- 
riod, therefore,  when  it  can  contain  no  baryta  dissolved, 
acquires  an  alkaline  reaction. 

The  organic        From  this  it  is  plain,  that  the  organic  acids  present 
juice  are  not  in  the  juice,  the  lactic  and  inosinic  acids,  &c.,  taken 
neutralize       together,   are  not  in  sufficient  quantity  to  form  neu- 
'lles*    tral  salts  with  the  alkalies  contained  in  it,  potash  and 
kreatinine ;  and  this  necessarily  implies  that  the  acid 
reaction  of  the  juice  of  flesh  is  caused  by  the   pres- 
ence of  acid  salts  of  the  alkalies  with  the  three  acids, 
—  phosphoric,  lactic,  and  inosinic  acid.     Inosinic  acid 
constitutes  too  small  a  part  of  the  juice  to  allow  us  to 
ascribe  to  it  a  perceptible  share  in  producing  the  acid 
The  acidity    quality  of  that  fluid;  and  this  acidity  depends,  there- 
depVnd'^on6    fore,  on  the  presence  of  acid  alkalic  lactate  and  acid 
alkalie  phosphate  (phosphate  with  one  atom  of  alkali) ; 
or>  m  otner  words,  of  neutral  alkalic  lactate  and  phos- 
phate, along  with  free  lactic  and  phosphoric  acids. 

It  is  obvious,  that  these  two  acids  are  shared  be- 
tween the  bases  present,  and  that  the  amount  of  free 
acid  present  must  stand  in  a  definite  relation  to  the 
quantity  of  the  bases. 


IN    THE    JUICE    OF    FLESH.  83 

Between  the  two  acids,  so  far  as  they  are  uncom-  Equilibrium 
bined,  an  equilibrium  is  established ;  the  quantities  of  these  free 
the  free  acids  are  proportional  to  their  affinity  or  pow- 
er of  combination. 

If  we  suppose  the  quantity  of  one  of  these  free 
acids  to  be  by  any  means  increased  in  the  juice  of 
flesh,  that  portion  of  the  other  which  is  free  must  in 
like  manner  increase ;  and  if,  by  any  means,  the 
amount  of  the  one  free  acid  be  diminished,  the  free 
portion  of  the  other  must  diminish  in  the  same  pro- 
portion, so  that  a  new  equilibrium  may  be  established 
between  the  free  portions  of  both.  If,  for  example, 
a  portion  of  phosphoric  acid  be  added  to  that  present 
in  the  juice,  a  part  of  this  must  seize  on  a  part  of  the 
alkali  of  the  alkalic  lactate;  thus  a  new  quantity  of 
acid  phosphate  of  the  alkali  will  be  formed,  and  a 
corresponding  amount  of  lactic  acid  set  free.  Exactly 
in  the  same  way  must  a  corresponding  quantity  of 
phosphoric  acid  be  set  free,  when  the  amount  of  lac- 
tic acid  present  is  in  any  way  increased. 

Now,  since  the  quantity  of  phosphoric  acid  in  the 
juice  is  sufficient  to  neutralize  all  the  alkali  present, 
white  the  organic  acids  are  present  in  smaller  pro- 
portion and  do  not  suffice  to  form  neutral  salts  with 
the  alkali,  it  follows  that  the  removal  of  lactic  acid 
would  give  rise  to  the  production  of  neutral  phos- 
phates, and  the  removal  of  phosphoric  acid  would 
cause  the  formation  of  neutral  lactates,  along  with  free 
alkali. 

The  salt  of  phosphoric  acid,  which  is  formed  when  When  either 
all  organic  acids  are  removed  from  the  juice  of  flesh,  acfd^f?  the 
although  neutral   in   composition,  has  an    alkaline  re-  acidSare°reC- 
action ;  and  when  all  the  phosphoric  acid  is  removed,  SsJfue  is  eai. 
there  age  left  salts  of  organic  acids,  which,  from  the  k< 
f   presence  of  free   alkali,  also  possess  an  alkaline  re- 
action. 


84  THE    FUNCTION    OF    LACTIC    ACID. 

Explanation        The  preceding  considerations  naturally  lead  to  the 

of  some  pro-  . 

cesses  in  the  explanation  of  some  processes  in  the  animal  organism. 
If  the  stomach  obtain  from  the  blood  the  same  acids 
which  we  have  found  to  exist  in  the  juice  of  flesh,  the 
blood  must  possess,  during  digestion,  a  stronger  alkaline 
quality  than  it  has  in  the  normal  state  ;  and,  consequent- 
ly, if  the  blood  is  to  preserve  its  normal  condition,  it 
must  either  obtain  from  the  muscles  a  supply  of  acid, 
exactly  equal  to  that  which  has  passed  into  the  stomach, 
or  the  excess  of  alkali  must  be  conveyed  to  the  mus- 
cles, or  secreted  by  the  kidneys.  If  the  urine  of  the 
animal  were  acid  before  digestion,  it  must,  on  the  latter 
supposition,  become,  during  that  process,  transiently 
neutral  or  alkaline  ;  if  it  contained  a  certain  quantity  of 
free  alkali,  that  must  be  increased. 

The  function  of  the  kidneys,  as  has  long  been 
known,  consists  in  the  preservation  of  an  equilibrium 
in  the  quality  of  the  contents  of  the  blood ;  and  this 
includes  the  removal  of  products  of  the  change  of  mat- 
ter, and  of  all  such  substances  as  affect  the  normal  qual- 

What  pur-     ity  of  the  blood.     In  this  point  of  view,  the  solution  of 

pose  is  serv- 
ed by  the  lac-  the  question,  u  What  purposes  does  lactic  acid  serve  in 

the  organism  ?  "  is  of  peculiar  importance.     On  this 
point  I  have  made  some  experiments,  which  may  per- 
haps assist  us  in  approaching  nearer  to  the  solution. 
Lactic  acid         I  have,  in  the  first  place,  repeatedly  endeavoured  to 

does  not  r  .       r   .       .    J 

occur  in        detect  the  presence  of  lactic  acid  in  fresh  urine,  pos- 
urine.  sessing  the  usual  acid  reaction.     But  I  have  not  been 

fortunate  enough,  with  the  aid  of  the  same  process  by 
means  of  which  I  succeeded  in  demonstrating  its  pres- 
ence in  the  juice  of  flesh,  to  detect  even  a  trace  of  lac- 
tic acid  in  the  urine  of  healthy  young  men.  The  urine 
was  evaporated  in  the  water-bath  to  the  consistence  of 
syrup,  mixed  with  diluted  sulphuric  acid,  and  the  acids 
thus  set  free  taken  up  by  alcohol.  The  alcoholic  solu- 


URINE    CONTAINS    NO    LACTIC    ACID.  85 

tion  was  evaporated  in  the  water-bath  to  a  thin  syrup, 
to  which  half  its  bulk  of  alcohol  and  then  ether  were 
added,  until  no  more  turbidity  ensued.  If  lactic  acid 
were  present,  it  must  have  been  dissolved  in  this  liquid, 
which  evidently  contained  much  hydrochloric  acid. 
The  ether  was  removed  by  evaporation,  the  residue  di- 
luted with  water,  and  acted  on,  when  cold,  with  an  ex- 
cess of  oxide  of  silver.  All  the  hydrochloric  acid  was  in 
this  way  separated  as  chloride  of  silver ;  had  lactic  acid 
been  present,  the  very  soluble  lactate  of  silver  must  have 
been  formed  ;  but  no  oxide  of  silver  remained  in  the 
filtered  solution.  The  addition  of  milk  of  lime  precipi- 
tated no  oxide  of  silver,  and  the  solution  thus  neutral- 
ized gave  on  evaporation  a  small  quantity  of  very  pure 
urea,  but  no  lactate  of  lime. 

Putrid  urine,  treated  in  the  same  way,  yielded  a  little 
acetate  of  lime  in  slender  needles,  but  in  no  instance 
lactate  of  lime. 

The  urine  of  healthy  men,  which  has  an  acid  reac- 
tion, contains,  therefore,  no  lactic  acid,  and  no  substance 
from  which  lactic  acid  can  be  formed  during  the  putre- 
faction of  urine.* 

With  respect  to  the  presence  of  lactic  acid  in  alka-  Jt  camiot  be 
line  urine,  the  following  experiment  is  sufficiently  de-  fheurine" 
cisive.     Three  persons,  among  whom  were  my  two  as-  ^emaiiyen 
sistants,  took  a  quantity  of  lactate  of  potash  sufficient  to 
have  yielded  an  ounce  of  lactate  of  zinc.     All  the  urine 
for  the  twro  subsequent  hours  was  collected.     In  each 
case  the  urine,  before  the  experiment,  had  an  acid  re- 

*  The  absence  of  lactic  acid  in  the  urine  which  I  examined 
does  not  exclude  the  opinion,  that  in  certain  conditions  lactic 
acid  may  occur  in  the  urine,  as  occurs  in  regard  to  other  constit- 
uents of  the  body,  which  are  not  found  in  the  urine  of  healthy 
persons,  while  they  may  be  detected  in  that  fluid  in  certain  pa- 
thological states. 

8 


86  LACTIC   ACID   SUPPORTS  RESPIRATION. 

action  ;  that  which  was  passed  immediately  after  taking 
the  lactate  was  strongly  alkaline,  and  the  potash  was 
easily  detected  in  it,  the  quantity  of  that  base  present 
exceeding  that  in  ordinary  urine.  But  it  was  impossi- 
ble to  detect  the  lactic  acid  in  this  urine  ;  it  had  entirely 
disappeared  during  its  passage  through  the  blood. 
The  lactic  From  this  it  plainly  appears,  that  the  lactic  acid  in 

acid  is  con- 
sumed in  res-  the   organism    is  employed  to  support  the  respiratory 

process,  and  the  function   performed  by  sugar,  starch, 
and  in  general  all  those  substances  which,  in  contact 
Function  of   with   animal    matter,  are  convertible    into  lactic  acid, 
i^mXnge'r    ceases  to  be  an  hypothesis.     These  substances  are  con- 
verted in  the  blood  into  lactates,  which  are  destroyed  as 
fast  as  they  are  produced,  and  which  only  accumulate 
where  the  supply  of  oxygen  is  less,  or  where  some 
other  attraction  is  opposed  to  the  agency  of  that  ele- 
ment.    When  we  consider  that  the  urine  of  graminiv- 
orous animals  contains  a  large  quantity  of  free  alkali, 
which  is  secreted  from  the  blood ;  that,  consequently, 
in  the  blood  a  current  of  dissolved  alkalies  is  carried 
through  the  whole   mass  of  the   body,  and  especially 
through  the  substance  of  the   muscles,  while  the  fluid 
which  is  in  contact  with  the  external  part  of  the  blood- 
vessels and  lymphatics  (the  juice  of  flesh)  retains  an 
Some  cause     acid  reaction,  we  perceive  that  a  cause  must  necessarily 
thlTremovai    be  in  action  at  these  points  which  prevents  the  removal 
acidaV66     of  the  free  acids,  or,  if  they  are  removed,  reproduces 
them  at  each  moment  of  time. 

The  blood-vessels  and  lymphatics  contain  an  alkaline 

fluid,  while  the  surrounding  fluid,  that  of  the  flesh,  is 

acid ;  the  tissue  of  which  the  vessels  are  composed  is 

permeable  for  the  one   or  the  other  of  these    fluids. 

Thecondi-     Here,  then,  are  two  conditions  favorable  to  the  produc- 

eiectricai       tion  of  an  electrical  current,  and  it  is  far  from  improb- 

present. &  *    able  that  such  a  current  takes  a  certain  share  in  the 


POTASH  ABOUNDS  IN  FLESH  ;  SODA  IN  BLOOD.   87 

vital  processes,  although  its  action  be  not  always  indi- 
cated by  proper  electrical  effects.* 

I  have  already  mentioned,  that  the  juice  of  flesh,  in  Potash  pre- 

.  ponderatesin 

all  animals,  is  particularly  rich   in  potash,  and  that  it  the  juice  of 
contains  also  chloride  of  potassium,  with  only  traces  of 
chloride  of  sodium.    Now,  as  every  constant  peculiarity 
in  the  form  or  in  the  composition  of  any  part  of  the  body 
has  a  significance  of  its  own,  this  fact,  namely,  the  pre- 
dominance of  salts  of  potash  and  of  chloride  of  potas- 
sium in  the  juices  of  flesh,  appears  to  me  to  be  so 
much  the  more  worthy  of  attention,  that,  in  the  blood, 
only  proportionally  small  quantities  of  the  salts  of  pot- 
ash, and  preponderating  quantities  of  the  salts  of  soda,  Soda  prepon- 
derates in  the 
and  of  common  salt,  are  present.  blood. 

To  give  a  specific  direction  to  our  views  on  the  sub-  Relative  pro- 
ject of  these  differences,  I  have  thought  it  advisable  to  potash  and 

,  .    ,       ,  ,      .  soda  in  flesh 

make  some  experiments,  in  which  the  relative  propor-  a'nd  blood, 
tions  of  the  compounds  of  sodium  and  potassium  in  the 
blood,  and   in  the  juice  of  the   flesh,  were  determined 
comparatively  in  different  animals. 

In  these  determinations  the  phosphoric  acid  was  pre-  Method 
cipitated  from  the  fluid  of  flesh  by  baryta,  the  filtered  er 
liquid  evaporated  to  dryness,and  the  residue  incinerated. 
The  ashes  thus  obtained  are  very  fusible  and  of  pecu- 

*  Professor  H.  Buff  has,  at  my  request,  constructed  a  pile, 
consisting  of  disks  of  pasteboard  moistened  with  blood,  of  mus- 
cular substance  (flesh),  and  of  brain.  This  arrangement  caused 
a  very  powerful  deviation  of  the  needle  of  the  Galvanometer, 
indicating  a  current  in  the  direction  from  the  blood  to  the  muscle. 

When  water  was  substituted  for  the  brain,  the  action  was  much 
weaker.  The  current  arising  from  contact  of  the  blood  alone 
with  the  platinum  was,  in  this  case,  in  the  direction  opposite  to 
that  of  the  current  just  mentioned.  The  electrician  will  find 
nothing  surprising  in  this,  since  the  blood  has  an  alkaline,  the 
flesh  an  acid,  reaction,  while  the  brain  has  a  scarcely  perceptible 
degree  of  alkalinity. 


88 


PROPORTIONS  OF  POTASH  AND  SODA 


Kesults 


in  the  Fowl, 


Ox, 


Horse, 


Fox, 


liar  character,  consisting  almost  entirely  of  cyanate  of 
potash  and  cyanide  of  potassium,  exactly  as  in  the  ashes 
of  an  alkaline  urate.  When  these  ashes  are  dissolved 
in  hydrochloric  acid,  effervescence  ensues,  as  with  a 
carbonate  from  the  decomposition  of  the  cyaniq  acid  ; 
a  certain  amount  of  sal  ammoniac  is  formed,  and  hy- 
drocyanic acid  is  abundantly  disengaged.  If  bichloride 
of  platinum  be  now  added,  to  separate  the  potash  from 
the  soda,  the  precipitate  which  is  formed  contains  am- 
monium-chloride of  platinum,  by  which  the  determina- 
tion of  the  potash  is  rendered  inaccurate.  It  is  there- 
fore necessary,  before  adding  the  bichloride  of  platinum, 
to  evaporate  the  solution  of  the  ashes  in  hydrochloric 
acid  to  dryness,  to  ignite  the  residue,  and  thus  expel  the 
sal  ammoniac. 

In  the  analyses  made  by  Henneberg  of  the  blood  of 
fowls,  for  which  the  blood  of  all  the  fowls  used  in  my 
researches  on  the  juices  of  their  flesh  was  employed, 
there  were  obtained,  including  the  chloride  of  sodium, 
for  100  parts  of  soda,  40.8  parts  of  potash.  The  juice 
of  the  flesh  of  the  same  fowls  yielded,  for  3.723  gms. 
of  double  chloride  of  platinum  and  potassium,  0.374 
gm.  of  chloride  of  sodium. 

Ox-blood  gave,  for  0.184  gm.  of  chloride  of  platinum 
and  potassium,  1.133  gm.  of  chloride  of  sodium. 

The  juice  of  ox-flesh  gave,  for  1.933  gm.  of  chloride 
of  platinum  and  potassium,  0.2536  gm.  of  chloride  of 
sodium. 

Horse-blood  gave,  for  1.351  gm.  of  chloride  of  so- 
dium, 0.341  gm.  of  chloride  of  platinum  and  potas- 
sium. 

The  juice  of  horse-flesh  gave,  for  4.414  gm.  of  chlo- 
ride of  platinum  and  potassium,  0.544  gm.  of  chloride 
of  sodium. 

The  juice  from  the  flesh  of  a  fox,  killed  in  the  chase. 


IN    BLOOD   AND    IN    FLESH.  89 

gave,  for  1.474  gm.  of  chloride  of  platinum  and  potas- 
sium, 0.250  gm.  of  chloride  of  sodium. 

The  juice  from  the  flesh  of  the  pike  gave,  for  1.964  and  Pike, 
gm.  of  chloride  of  platinum  and  potassium,  0.065  gm. 
of  chlaride  of  sodium. 

These  results,  when  reduced  and  tabulated,  give,         Tabular 

view. 

Potash  in          Potash  in 
the  Blood.         the  Flesh. 

For  100  parts  of  soda  in  the  Fowl,  40.8  384 

"                        "          Ox,  5.9  279 

"                        "          Horse,  9.5  285 

"                       "          Fox,  "  214 

"                        "          Pike,  "  497 

It  is  hardly  necessary  to  state,  that  these  numbers  These  num- 
only  express  approximatively  the  proportions  of  potash  proximative. 
to  soda  in  the  flesh,  because  it  is  impossible  to  obtain 
the  juice  of  the  flesh  of  the  ox,  horse,  and  fowl  free 
from  blood  tind  lymph,  fluids  which  contain  much  soda. 
Had  it  been  possible  to  obtain  the  juice  of  flesh  unmixed  The  juice  of 
with  blood  and  lymph,  the  proportion  of  potash  to  soda  possibly 
would  have  come  out  much  higher ;  so  much  so,  indeed,  soda!*'" 
that  the  conclusion  that  salts  of  soda  form  no   part 
of  that  fluid  is   not  destitute  of  probability;  and  if,  as 
is  supposed,  the  lymphatic  vessels  possess  the  power  of 
taking  up  the  salts  of  soda  which  pass  from  the  capillaries 
into  the  substance  of  the  muscles,  and  returning  these 
salts  to  the  larger  blood-vessels,  the  fact  just  mentioned 
admits  of  a  very  simple  explanation. 

From   the   great  difference  of  chemical  nature  and  The  permea- 
qualities  in  the  fluids  circulating  in  the  different  parts  of  vesseis°of  the 

.      r,  „  ,,     ,  ^   •,  .  various  fluids 

the  organism,  it  follows,  that  there  must  be  a  very  re-  must  be  dif- 
markable  difference  in  the  permeability  of  the  pari- 
etes  of  the  vessels  for  these  fluids.  Were  this  perme- 
ability in  all  cases  the  same,  there  must  have  been 
found  as  much  of  the  salts  of  soda  and  potash  in  the 
juice  of  flesh  as  in  the  blood ;  but  the  blood  of  the  ox 
8* 


90  IMPORTANCE    OF    CHLORIDE    OF    SODIUM 

and  the  fowl  contains  nearly  a  third  of  its  whole  saline 
contents  of  chloride  of  sodium,  while  hardly  a  trace  of 
this  compound  occurs  in  the  juice  of  flesh. 
Potash  pre-         The  vessels  which  secrete  milk  must  stand  in  a  simi- 

ponderates  . 

in  milk.  lar  relation  to  the  blood-vessels  ;  for  in  the  milk^of  the 
cow  the  salts  of  potash  preponderate  very  greatly  over 
those  of  soda,  and  are  present  also  in  much  larger  quan- 
tity than  in  the  saline  constituents  of  blood. 

Accumuia-          In  some   pathological  conditions  there  has  been  ob- 
aclds'in ree     served,*  at  points  where  bones  and  muscles  meet,  an 
s£ues.m°   '    accumulation  of  free  lactic  and  phosphoric  acids,  which 
has  never  been  perceived  at  those  points  in  the  normal 
state.     The  solution  and  removal  of  the  phosphate  of 
lime,  and  therefore  the  disappearance  of  the  bones,  is  a 
causing  the    consequence  of  this  state.     It  is  riot  improbable  that  the 
an?ePoTthe     cause,  or  one  of  the  causes,  of  this  separation  of  acid 
from  the  substance  of   the  muscle  is  this,, —  that  the 
vessels   which  contain  the  fluid  of  the  muscles  have 
undergone  a  change,  whereby  they  lose  the  property  of 
retaining  within  them  the  acid  fluid  they  contain, 
importance         The  constant  occurrence  of  chloride  of  sodium  and 
Mdhuntotto  phosphate  of  soda  in  the  blood,  and  that  of  phosphate 
of  potash  and  chloride  of  potassium  in  the  juice  of  flesh, 
justify  the  assumption  that  both  facts  are  altogether  in- 
dispensable for  the  processes  carried  on  in  the  blood  and 
in  the  fluid  of  the  muscles. 

Use  of  salt.  Proceeding  on  this  assumption,  the  necessity  for  add- 
ing common  salt  to  the  food  of  many  animals  is  easily 
explained,  as  well  as  the  share  which  that  salt  takes  in 
the  formation  of  blood,  and  in  the  respiratory  process, 
inland  plants  It  is  a  fact,  now  established  by  numerous  analyses, 
that  the  ashes  of  plants,  growing  at  a  certain  dis- 


*  Schmidt,  Annalen  der  Chemie  und  Pharmacie,  Vol.  LXI. 
p.  329. 


TO    THE    FORMATION    OF   BLOOD.  91 

tance  from  the  sea,  contain  no  soda,  or  only  traces  of 
that  base. 

The  ordinary  potashes  of  inland  countries  give  most  contain  no 

£  .      soda,  and  lit- 

convincing  proof  of  this  ;  for  they  but  rarely  contain  tie  chloride 
any  carbonate  of  soda  ;  and  when  a  compound  of  so- 
dium occurs  in  them,  it  is  not  phosphate  or  sulphate  of 
soda,  but  chloride  of  sodium.  Wheat,  barley,  oats, 
root-crops,  and  plants  with  esculent  leaves,  in  the  Oden- 
wald,  in  Saxony,  and  in  Bavaria,  contain  only  salts  of 
potash,  without  salts  of  soda  ;  and  if,  in  several,  soda 
sometimes  occurs,  chlorine  is  also  present,  and  both  are 
in  the  proportion  to  form  sea  salt. 

In  plants  growing  in  maritime  countries  near  the  sea-  The  same 
coast,   these   proportions  are   altered.     Wheat,  pease,  mariume dis- . 
and  the  other  leguminous  plants,  in  the  Netherlands,  soda^ndlx)" 
contain  phosphate  of   potash,  and   also   phosphate  of  ash> 
soda,  the  phosphate  of  potash,  however,  always  pre- 
dominating. 

This  is  the  case  even  in  sea  plants,  living  in  a  medi-  Even  sea 
um  which  contains,  compared  with  its  amount  of  soda  urn^mS? 
or  sodium,  a  mere  fraction  of  pota'sh.     All  sea  plants  sodT.h  l 
contain  much  more  potash  than  soda. 

In  respect  to  these  two  bases,  therefore,  the  food  of 
animals  is  not  in  all  places  of  the  same  quality  or  com- 
position. 

An  animal,  feeding  on  plants  which  contain  phos-  Necessity  of 
phates  of  other  bases,  along  with  some  compound  of  sodhmftoan- 

i  T  i  i      i        i  i          i     t          e>  imals  feeding 

soda  or  sodium,  produces  in  its  body  the  phosphate  01  On  inland 
soda  indispensable  to  the  formation  of  its  blood.     But  plar 
an  animal,  living  inland,  obtains  in  the  seeds,  herbs, 
roots,  and  tubers  which  it  consumes,  only  salts  of  pot- 
ash.    It  can  produce,  from  the  phosphates  of  lime  and 
magnesia,  by  decomposition  with  the  salts  of  potash, 
only  phosphate  of  potash,  the  chief  inorganic  constit- 
uent of  its  flesh  ;  but  no  phosphate  of  soda,  which  is  a 


92        USES  OF  THE  PHOSPHATE  OF  SODA 

compound  never  absent  in  its  blood.  Whence,  there- 
fore, does  it  obtain  this  phosphate  of  soda  ?  The  true 

Action  of  answer  to  this  question  is  given  by  a  study  of  the  ac- 
'tashor?0  tion  of  phosphate  of  potash  on  chloride  of  sodium. 

sodium6  °  Phosphate  of  potash,  with  2  atoms  of  potash  (tribasic 
phosphate  of  potash,  with  2  atoms  of  fixed  base  and  1 

!2  1C  O  ) 
J  ,  is   deliquescent, 
HO* 

hardly  crystallizable,  and  has  a  very  feeble  alkaline 
reaction. 

When  we  supersaturate  phosphoric  acid  (tribasic) 
with  potash,  and  evaporate  to  crystallization,  a  salt  is 

deposited,  which  has  an  acid  reaction  =  P  O5  <  >  . 

There  is  no  salt  which  loses  half  the  amount  of  base 
it  contains  so  easily  as  the  phosphate  of  potash. 
If  phosphoric  acid  be  neutralized  with  potash,  and 
chloride  of  sodium  added  to  the  solution,  and  the 
whole  left  to  spontaneous  evaporation,  a  phosphate 
crystallizes,  which  contains  both  potash  and  soda 

/  (Na°)\ 

I  the  tribasic  salt  P  O5  J    K  O  \    1  ,  while  chloride  of 

V  i  HO)  / 

potassium  is  found  in  the  mother  liquid. 

It  is  obvious,  that  phosphate  of  potash  is  decomposed 
when  in  contact  with  chloride  of  sodium  ;  part  of  the 
potassium  combines  with  the  chlorine,  while  the  sodi- 
um replaces  it  in  the  phosphate,  phosphate  of  soda 
being  produced.* 

*  It    is    evident    that    the    tribasic    salt    above    mentioned, 

r  Na  O  } 
P  Os  <  K  O  >  may  equally  well  be  represented  as  a  double  salt, 

(HO) 
composed  of  phosphate  of  soda  and  phosphate  of  potash. 


—  W.  G. 


CONTAINED    IN    THE    BLOOD.  93 

In  this  way  we  can  understand  the  formation  of 
phosphate  of  soda  in  the  body  of  an  animal,  which  ob- 
tains in  its  food,  along  with  phosphate  of  potash,  or 
earthy  phosphates  and  salts  of  potash,  no  compound  of 
soda  except  chloride  of  sodium  ;  and  when,  in  inland 
countries,  the  food  does  not  contain  common  salt 
enough  to  produce  the  phosphate  of  soda  necessary 
for  the  formation  of  the  blood,  then  more  salt  must 
be  added  to  the  food.  From  the  common  salt  is  pro- 
duced, in  this  case,  by  mutual  decomposition  with  phos- 
phate of  potash  or  with  earthy  phosphates,  the  phos- 
phate of  soda  of  the  blood. 

That  phosphate  of  soda  is  indispensable  to  the  nor-  The  phos- 
mal  constitution  of  the  blood,  and  that  the  processes  fn^he^bioo 
which  go  on  in  that  fluid  cannot  be  replaced  by  phos- 
phate  of  potash,  seems  to  me  to  be  an  opinion  fully 
justified  by  the  properties  of  these  two  salts. 

Through  the  blood,  the  carbonic  acid  formed  in  the 
body  is  conveyed  out  of  it,  and  the  alkaline  quality  of 
the  blood  has  a  very  decided  share  in  its  property  of  importance 
thus  taking  up  carbonic  acid  ;  as,  on  the  other  hand,  hig^Se^rue 
the  chemical  nature  of  the  compound,  on  which  the  afkaUnuV^f 
alkaline  reaction  of  the  blood  depends,  exerts  the  most  lhe 
marked  influence  on  the  power  of  the  blood  again  to 
give  off  the  carbonic  acid  which  it  had  absorbed. 

It  is  known  that  freshly  drawn  blood,  by  mere  agita-  Relation  of 

.•  •,-!       •      i  •          -i  TV  /»  i      j         blood  to  car- 

tion  with  air,  by  passing  through  it  a  current  of  hydro-  bonicacid 
gen  gas,  or  in  the  vacuum  of  the  air-pump,  gives  off  g£ 
carbonic  acid.     From  the  experiments  of  Scheerer,  at 
which  I  had  the  opportunity  of  being  present,  and  of 
others,  it  is  known,  moreover,  that,  for  example,  the 
clear  serum  of  ox-blood,  free  from  blood  corpuscules,  Experiments 
absorbs  nearly  twice  its  volume  of  carbonic  acid,  that 
is,  as  much  more  as  the  same  bulk  of  water  can  ab- 
sorb at  the  same  temperature.     The  greater  absorbing 


94         RELATION  OF  BLOOD  AND  SERUM 

power  of  the  serum  is  determined  by  a  chemical  at- 
traction, by  a  substance  which  has  an  alkaline  reac- 
tion. In  fact,  it  is  observed,  that,  when  this  alkaline 
reaction  is  destroyed,  when  acetic  acid  is  added  to  the 
blood  saturated  with  carbonic  acid,  the  excess  of  car- 
bonic acid  is  at  once  given  off.  Bat  the  same  thing 
happens  when  this  blood  is  agitated  with  gases,  such  as 
hydrogen,  for  a  long  time,  and  the  gases  renewed  from 
time  to  time. 

Blood,  when  not  saturated  with  carbonic  acid,  gives 
off,  in  vacuo,  nearly  5  p.  c.  of  its  volume  of  that  gas  ; 
the  addition  of  acetic  acid  increases  the  quantity  of  the 
carbonic  acid  disengaged  ;  but  even  under  these  cir- 
cumstances, not  more  than  half  its  volume  of  carbonic 
acid  can  be  obtained  from  blood. 
The  serum  of  Had  the  greater  absorptive  power  of  the  serum  of 

blood  con-  .  . 

tains  no        blood  for  carbonic  acid  been  dependent  on  the  pres- 

carbonate  „         .  ,    .  ,  . 

of  soda.  ence  of  carbonate  of  soda,  and  its  conversion  into  bi- 
carbonate of  soda,  this  would  imply  that  the  blood 
must  contain  at  least  its  own  volume  of  carbonic  acid 
in  the  form  of  neutral  carbonate  of  soda.  If  blood 
contained  its  own  volume  of  carbonic  acid  in  the  form 
of  neutral  carbonate,  and  no  free  carbonic  acid,  this 
blood  would  absorb  exactly  twice  its  volume  of  car- 
bonic acid  (one  volume  to  form  bicarbonate,  the  other 
to  saturate  the  liquid  as  it  would  an  equal  bulk  of 
water),  and  the  addition  of  acids  which  decompose  the 
carbonate  of  soda  must,  in  that  case,  disengage  a  vol- 
ume of  carbonic  acid  equal  to  twice  the  volume  of  the 
blood.  The  acid  would,  in  fact,  disengage  three  vol- 
umes of  carbonic  acid,  one  of  which  is  retained  by  the 
liquid.  In  the  experiments  of  Scheerer,  serum  of 
blood,  which  had  absorbed  twice  its  volume  of  carbonic 
acid,  only  yielded  half  as  much  carbonic  acid  as  ought 
to  have  been  given  off  on  the  above  supposition. 


TO    CARBONIC    ACID   GAS.  95 

There  was  less  than  one  volume  of  free  carbonic  acid 
present  in  the  serum,  and  the  liquid  retained,  for  that 
reason,  a  proportionally  greater  quantity  of  carbonic 
acid.* 

When  2,000  cubic  centimetres  of  ox-blood,  mixed  The  author's 

.  experiments 

with  twice  their  volume  of  water,  are  heated  to  boil-  to  prove  this. 
ing,  and  the  coagulum  pressed  out,  we  obtain  about 
2,000  c.  c.  (^d  of  the  whole  liquid)  of  an  alkaline  liquid. 
If  the  alkaline  reaction  of  this  liquid  arises  from  car- 
bonate of  soda,  these  2,000  c.  c.  must  contain  Jd  of  the 
whole  carbonate  of  soda  contained  in  that  volume  of 
blood.  When  concentrated  to  \d  by  evaporation,  this 
liquid  must  contain  exactly  as  much,  if  concentrated  to 
Jth,  twice  as  much,  to  ^th,  four  times  as  much,  and  to 
§\th,  eight  times  as  much,  &c.,  carbonate  of  soda  as  an 
equal  volume  of  blood. 

Now  I  have  concentrated  this  liquid  to  ^th  of  its  Highly  cou- 

.  .  .  centrated  se- 

volume,  in  which  state  it  must,  on  the  supposition  for-  rum  absorbs 
merly  mentioned,  contain  166  times  as  much  carbonate  acid. 
of  soda  as  an  equal  volume  of  blood,  if  that  salt  were 
an  ingredient  of  blood.     When  brought  in  contact  with 


*  Annalen  der  Chemie  und  Pharmacie,  Vol.  XL.  p.  30. 
I.    60  vols.  of  serum  absorbed  124  vols.  of  carbonic  acid. 
II.     56  "  111  " 

116  235 

After  the  addition  of  30  cubic  centimetres  of  acetic  acid  to  the 
first  portion,  and  of  28  c.  c.  to  the  second  portion  of  serum,  in 
all,  after  the  addition  of  58  c.  c.  of  acetic  acid,  there  were  disen- 
gaged, from  174  vols.  of  the  mixture  (116  vols.  of  serum  and  58 
vols.  of  acetic  acid),  89  vols.  of  carbonic  acid.  Had  the  blood 
contained  its  own  volume  of  carbonic  acid  in  the  form  of  neutral 
carbonate  of  soda,  it  must  have  given  off  177  vols.  of  carbonic 
acid ;  that  is,  235  —  58  (the  volume  which  would  be  retained  by 
the  acetic  acid).  According  to  these  experiments,  the  actual 
amount  of  carbonic  acid  present  in  the  blood  is  calculated  to  be 
28  per  cent,  of  its  volume. 


96  THE   ABSORBENT    POWER    OF    SERUM 

carbonic  acid,  this  concentrated  liquid  absorbed  3  times 
its  own  volume  ;  20  c.  c.  absorbed  60  c.  c.  of  carbonic 
acid.     Now  it  is  certain,  that  if  this  absorptive  power 
had  been  dependent  on  the  presence  of  carbonate  of 
•  soda,  the  solution,  saturated  with  carbonic   acid,  must 
have  given  off,  when  mixed  with  acids,  3  times  its  orig- 
inal volume  of  carbonic  acid,  of  which  £d  would  be  re- 
tained by  the  liquid.     From  20  c.  c.,  therefore,  of  the 
but  does  not  concentrated  liquid,  there  should  have  been  obtained 

give  off  a 

trace  when     40  c.  c.  of  free  carbonic  acid.     But  this  liquid,  when 

acids  are  .  .77  /• 

added  to  it.    acted  on  by  acids,  gave  off  no  appreciable,  trace  of  car- 
bonic acid  gas. 

According   to   the    observations   of    Marchand,    this 

liquid  is  not  free  from  carbonic  acid,  when  it  has  been 

mixed  with  another  acid,  for  by  heating  it  carbonic  acid 

7.5  cubic        is  expelled.     But  even  on  the  most  favorable  supposi- 

rumcanno^"  tion,  that  is,   if  we  admit  that  the  liquid  is  saturated 

thanT5thsre  with  carbonic  acid,  it  is  obvious  that  no  more  carbonate 

carbonate  of   °f  s°da  can  be  contained  in  it  than  corresponds  to  the 

"^  volume  of  carbonic  acid  required  to  saturate  the  jj^th 

part  of  the  volume  of  the  serum.     This  amounts,  for 

1000  c.  c.  of  serum,  to  so  much  soda  as  is  saturated  by 

6  c.  c.  of 'carbonic  acid  gas  =  0.026  gm.  of  carbonate 

of  soda,  or  fths  of  a  grain. 

butitabsorbs      The  serum  of  blood  absorbs,  therefore,   166  times 
thneTmore     more  carbonic  acid  than  could  be  absorbed  by  the  very 
tban°thLaCld  largest  proportion  of  carbonate  of  soda  which  it  can  be 
could™*16       supposed  to  contain  ;  and  consequently  the  carbonate 
of  soda,  if  it  be  present  at  all  in  the  liquor  sanguinis, 
can  have  but  a  most  insignificant  share  in  the  absorp- 
tive power  of  that  fluid  for  carbonic  acid. 

This  depends       As  the  study  of  the  serum  and  the  analysis  of  the 
phate6of  so-  ashes  of  blood  prove,  the  alkaline  quality  of  the  blood 
depends  on  the  presence  of  phosphate  of  soda.      In- 
deed, it  may  well  be  asked,  from  what  source  can  car- 


DEPENDS  ON  PHOSPHATE  OF  SODA.        97 

bonate  of  soda,  if  we  suppose  it  to  be  present,  be  de-  . 
rived,  in  the  blood  of  a  man  living  on  bread  and  flesb, 
or  of  an  animal  feeding  on  flesh,  since  in  these  kinds 
of  food  the  alkalies  and  phosphoric  acid  are  present  in 
the  proportion  in  which  they  form  salts  with  2  and  with 
3  atoms  of  fixed  base  ?  * 

There  is  no  known  salt  the  chemical  characters  of  Remarkable 
which  approach  more  closely  to  those  of  the  serum  of  phosphate  of 
blood  than  the  phosphate  of  soda  ;  there  is  none  more 
fitted  for  the  absorption  and  entire  removal  from  the  or- 
ganism of  carbonic  acid.     This  salt  behaves  towards 
carbonic  acid  exactly  as  neutral  carbonate  of  soda ;  its 
aqueous  solution  absorbs    carbonic   acid    gas  with  the 
same  facility,  but  with  this  difference,  however,   that  it  not  only 

,  .    n  «    .  i'ii  absorbs,  but 

under  the  influence  of  the  same  causes  which  decom-  also  gives  oti; 
pose    the    neutral    carbonate    and    the    bicarbonate   of  with  great  fit- 
soda,  this  solution  gives  off  the  carbonic  acid  which  it 
has  absorbed  much  more  easily,  and  also  more  com- 
pletely, since  it  does  not,  like  soda,  in  its  conversion 
from    bicarbonate    into    neutral  carbonate,   retain   any 
portion  of  carbonic  acid. 

When  carbonic  acid  gas  is  placed  in  contact  with  a 
solution  of  1  part  of  dry  phosphate  of  soda  (P  O5, 
2  Na  O,  H  O),  in  100  parts  of  water,  twice  as  much 
carbonic  acid  is  absorbed  as  an  equal  volume  of  water, 
at  the  same  temperature,  can  take  up.t 

*  The  experiments  of  Erdmann  on  the  incineration  of  wheat 
( Annalen  der  Chemie  und  Pharmacie,  Vol.  LIV.  p.  354)  leave  no 
doubt,  that  the  tribasic  phosphates  (with  3  atoms  of  fixed  base) 
in  these  ashes  are  derived  from  the  action  of  carbon  on  the 
phosphates  with  1  and  2  atoms  of  fixed  base,  at  a  red  heat,  or 
from  the  decomposition  of  chloride  of  sodium  in  contact  with 
these  phosphates.  In  the  analyses  of  Henneberg,  where  this 
last  cause  was  avoided,  the  formation  of  pyrophosphate  of  soda 
proves  that  the  blood  of  fowls  contains  tribasic  phosphate  of 
soda  with  two  atoms  of  fixed  base  (P  O5,  2  Na  O,  H  O). 

t  A  solution  of  phosphate  of  soda,  saturated  with   carbonic 

9 


98        IMPORTANCE  OF  THE  PHOSPHATE 

By  simple  agitation  with  air,  or  by  diminution  of  the 
atmospheric  pressure,  fds  of  the  absorbed  carbonic 
acid  are  given  off  at  the  ordinary  temperature  ;  by  con- 
tact with  fresh  carbonic  acid,  these  §ds  are  immedi- 
ately again  absorbed.* 

acid,  may  be  recommended  as  one  of  the  pleasantest  saline  pur- 
gatives. 

Experiments.  *  A  solution  of  1  part  of  dry  phosphate  of  soda,  P  Os,2  Na  O, 
H  O,  in  100  parts  of  water,  when  agitated  with  pure  carbon- 
ic acid  gas,  free  from  atmospheric  air,  absorbed  : 

I.     II.    III.    IV. 

Solution,  cubic  centimetres  .  .  .  59  38  62  56 
Carbonic  acid  absorbed  c.  c.  .  .  .  104  77  ]  14  112 
100  vols.  of  the  solution  absorb,  therefore,  176  203  183  200 
Mean  amount  of  gas  absorbed  by  100  vols.  of  solution  =  190  vols. 
The  water  which  had  been  used  for  the  solution  was  treat- 
ed in  the  same  way  and  absorbed  : 

I.          II.       III. 

Water,  c.  c 104        75        54 

Carbonic  acid  absorbed  c.  c.     .         .      98        64        52 
100  vols.  of  water  absorb,  therefore,      95        a5        98 
Mean  amount  of  gas  absorbed  by  100  vols.  of  water  =  92  vols. 
A  portion  of  the  solution  of  phosphate  of  soda,  as  above,  was 
saturated  with  carbonic  acid,  and  then  agitated   with   repeated 
portions  of  air,  as  long  as  any  carbonic  acid  was  expelled.     The 
solution  was  now  placed  in  contact  with  pure  carbonic  acid  gas, 
and  absorbed : 

I.       II.     III.     IV. 

Solution,  c.  c 62      67      68      89 

Carbonic  acid  absorbed  c.  c.      .         .         .88      91       99    116 
100  vols.  of  solution  absorb,  therefore,         143    134     145     130 

Mean  amount  absorbed  by  100  vols.  of  solution  =  138. 
A  similar  solution  of  phosphate  of  soda,  saturated  with  car- 
bonic acid,  was  deprived,  as  completely  as  possible,  of  that  gas, 
under  the  receiver  of  the  air-pump,  being  left  for  two  hours  un- 
der a  pressure  of  2"'.  When  again  placed  in  contact  with  car- 
bonic acid,  it  absorbed : 

I.        II.        III. 

Solution,  c.  c.  .  .  .  .  74  80  70 
Carbonic  acid  absorbed  c.  c.  .  .  99  107  96 
100  vols.,  therefore,  absorb  .  .  120  133  137 
Mean  amount  absorbed  by  100  vols.  of  solution  =  130. 


OF    SODA    IN    THE    BLOOD.  99 

By    the  spontaneous  evaporation   in  the  air  of  the  Uses  of  the 

•  /.  t        •  i  i  phosphate  of 

solution  of  phosphate  of  soda,  saturated  with  carbonic  soda  in  blood. 
acid,  the  whole  of  the  carbonic  acid  is  given   off,  and 
the  phosphate  is  left,  with  all  its  original  properties,  in- 
cluding its  alkaline  reaction. 

When  carbonic  acid  is  taken  up  by  the  blood,  there  Action  of 
is  established  between  the  phosphoric  and  carbonic  acids  on  the  blood. 
an  equilibrium,  similar  to  that  existing  in  the  juice  of 
flesh  between  the  phosphoric  and  lactic  acids.     In  the 
same  way  as  these  last  divide  between  them  the  potash 
of  the  juice,  so  do  the  carbonic  and  phosphoric  acids 
divide  between  them  the  soda  of  the  blood.     There  can 
be  no  circumstances  more  favorable  to  the  separation 
of  one  or  other  of  the  two  acids. 

If  we  assume,  that  the  carbonic  acid  seizes  a  portion 
of  the  soda,  we  may  imagine  that  the  phosphoric  acid, 
previously  combined  with  this  portion  of  base,  is  ex- 
pelled from  the  place  it  originally  occupied,  and  thus 
set  free ;  but  it  does  not  yet,  on  that  account,  separate 
from  the  compound.  We  can  say  that  the  carbonic  acid 
is  converted  into  carbonate  of  soda  only  when  the  free 
phosphoric  acid  has  been  removed,  and  employed  in 
another  quarter;  but  in  point  of  fact,  this  phosphoric 
acid,  thus  displaced,  is  always  present,  and  retains, 
unimpaired,  its  power  of  again  combining  with  the  ~__ 
soda.  The  slightest  cause,  coming  in  aid  of  its  affinity, 
so  as  to  give  it  the  preponderance  (and  to  this  category 
belong  all  causes  which  diminish  the  affinity  of  car- 
bonic acid  for  soda),  suffices  to  displace  the  carbonic 
acid,  and  to  reproduce  the  original  compound.  Agita- 
tion with  air ;  the  spontaneous  evaporation  of  the 
water  in  which  the  compound  is  dissolved;  the  dimi- 
nution of  the  atmospheric  pressure  ;  all  these  causes, 
which  have  no  effect  on  neutral  carbonate  of  soda,  pro- 
duce decomposition,  and  cause  the  separation  of  the 


100    PROPORTIONS  OF  LIME,  MAGNESIA,  JcC.,  IN  FLESH. 

carbonic  acid,  taken  up  by  the  phosphate  of  soda   in 
The  amount  the   blood.     In   this  manner,  the  amount  of  carbonic 

ef  carbonic  . 

acid  in  the     acid  in  the  blood  is  kept  at  a  constant  value.     If  more 

Wood  is  kept  .  .  . 

uniform.        carbonic  acid  enter  the   blood    from   the    body,    more 
phosphoric  acid  is  set  free  in  proportion,  and  thereby 
a  more  easy  and  complete  separation  of  the  carbonic 
acid  in  the  lungs  is  secured.     If  more  soda  be  taken 
up,  then  a  part  of  the  carbonic  acid,  which  would  other- 
wise have  escaped  by  the  lungs  and  skin,  is  expelled  by 
the  urinary  passage  in  the  form  of  carbonate  of  soda, 
influence  of        It  is  easy  to  foresee,  that  a  more  exact  study  of  the 
lies,  and  salts  influence  which  alkalies,  salts,   and  mineral  acids  ex- 

on  respira- 
tion, ert  on  the  respiratory  process  in  the  normal  state  must 

lead    to   the    most    beautiful   and   valuable   results   in 

regard  to  their  employment  in  various  diseases. 

flesVcon-°f        ^  ^as  a^rea(^y  been  pointed  out,  that  in  the  juice  of 

mtie  lime       ^es^  t^le  amount  °f  phosphate  of  lime,  compared  with 

that  of  phosphate    of  magnesia,  is  very    trifling.     In 

fact,  the  juice  of  ox-flesh  contains  so  little  lime,  that 

the   quantity   obtained    from    many   pounds    of    flesh 

amounted  only  to  a  few  millegrammes  (1  millegramme 

=T^th  of  a  grain,  nearly)  ;  but   in   the  juice  of  the 

flesh   of  fowls,  the   relative  proportions  of  these  two 

bases  admitted  of  more  exact  determination. 

Proportion  of      The  juice  of  fowl's  flesh  was  precipitated  by  baryta, 

magnesia  in    the  precipitate  dissolved  in  hydrochloric  acid,  the  bary- 

fowiJ.UK         ta  separated  by  sulphuric  acid,  and  then  the  phosphoric 

acid  removed  by  means  of  sesqui-chloride  of  iron  and 

ammonia.     The  lime  and  magnesia  then  remained  in 

solution.     There  were  obtained  0.72  gm.  of  carbonate 

of  lime,  and  0.431  gm.  of  phosphate  of  ammonia  and 

magnesia ;  or  for  10  parts,  by  weight,  of  lime,  39.2 

parts  of  magnesia. 

Proportion          The    proportion    of  the    phosphoric    acid    combined 

of  alkaline  ,  ,         .  ,  .1 

phosphates,    with   alkalies    to   that   united   with    magnesia,   in    the 


PRACTICAL  APPLICATION  OF  THE  RESULTS.    101 

juice  of  ox-flesh,  was  determined  in  the  following 
manner.  The  precipitate  formed  by  baryta  contains 
all  the  phosphoric  acid,  partly  combined  writh  baryta 
(as  P  O5,  3  Ba  O),  partly  with  magnesia  (as  P  O5, 
3  Mg  O).  This  precipitate  was  decomposed  by  sul- 
phuric acid,  and  the  liquid,  filtered  from  the  sulphate  of 
baryta,  was  precipitated  by  ammonia.  In  this  way  the 
magnesia  was  thrown  down,  in  the  form  of  the  usual 
double  phosphate.  The  liquid  filtered  from  this  pre- 
cipitate contained  the  phosphoric  acid  originally  com- 
bined with  alkalies,  and  when  mixed  with  sulphate  of 
magnesia  yielded  a  new  precipitate  of  the  same  double 
phosphate  of  ammonia  and  magnesia.  The  weight  of 
the  first  precipitate  was  to  that  of  the  second  as  0.2782 
to  0.974,  or  as  1  to  3.5.  For  2  atoms  of  phosphoric 
acid,  therefore,  combined  with  magnesia,  the  juice  of 
ox-flesh  contains  7  atoms  of  phosphoric  acid,  com- 
bined with  alkalies,  chiefly  potash.  In  another  ex- 
periment the  proportion  was  found  to  be  as  1  to  3.2. 


SECTION  III. 

Practical  Application  of  the  Results  of  the  Foregoing 
Investigation. 

WITH  reference  to  a  future    chemistry   of  alimen-  Effector 
tary  substances,  it  appears  from  these  researches,  that  flesh? 
by  the  boiling  of  flesh  an  essential  change  in  its  com- 
position is  effected.     According  to  the  duration  of  the 
boiling,  and  the  amount  of  Water  employed,  there  takes 
place  a  more  or  less  perfect  separation  of  the  soluble 
from  the  insoluble  constituents  of  flesh.    The  water  in 
which  flesh  has  been  boiled  contains  soluble  alkaline 
9* 


102 


FLESH  COMPLETELY  EXTRACTED 


phosphates,  lactates,  and  inosinates,  phosphate  of  mag- 
nesia, and  only  traces  of  phosphate  of  lime ;  the  boiled 
flesh  contains  chiefly,  with  the  fibrine,  &c.,  the  insolu- 
ble inorganic  constituents,  phosphate  of  lime  and  phos- 
phate of  magnesia. 

It  is  obvious,  that  if  flesh,  employed  as  food,  is 
again  to  become  flesh  in  the  body,  if  it  is  to  retain  the 
power  of  reproducing  itself  in  its  original  condition, 
none  of  the  constituents  of  raw  flesh  ought  to  be  with- 
drawn from  it  during  its  preparation  for  food.  If  its 
composition  be  altered  in  any  way,  if  one  of  the  con- 
stituents which  belong  essentially  to  its  constitution  be 
removed,  a  corresponding  variation  must  take  place 
in  the  power  of  that  piece  of  flesh  to  reassume  in  the 
living  body  the  original  form  and  quality,  on  which 
its  properties  in  the  living  organism  depend. 

It  follows  from  this,  that  boiled  flesh,  when  eaten 
without  the  soup  formed  in  boiling  it  (the  louilli  with- 
out the  bouillon),  is  so  much  the  less  adapted  for  nu- 
trition, the  greater  the  quantity  of  the  water  in  which 
it  has  been  boiled,  and  the  longer  the  duration  of  the 
boiling. 

When  finely  chopped  flesh  is  extracted  with  cold 
water,  it  loses  the  whole  of  the  albumen  contained  in 
it.  The  fibrinous  residue,  after  being  well  washed 
with  cold  water,  if  boiled  with  water  is  found  to  be 
perfectly  tasteless ;  it  is  cleai;  that  all  the  sapid  and 
odorous  constituents  of  flesh  exist  in  the  flesh  itself 
in  the  soluble  state,  and  consequently,  when  it  is  boiled, 
are  transferred  to  the  soup.  The  smell  and  taste  of 
roasted  flesh  arise  from  the  soluble  constituents  of  the 
juice,  which  have  undergone  a  slight  change  under 
the  influence  of  the  higher  temperature.  Flesh,  which 
has  been  rendered  quite  tasteless  by  boiling  with  water, 
acquires  the  taste  and  all  the  peculiarities  of  roasted 


BY    COLD    WATER.  103 

flesh,  when  it  is  moistened  and  warmed  with  a  cold 
aqueous  infusion  of  raw  flesh  which  has  been  evap- 
orated till  it  has  acquired  a  dark  brown  color.*     All 
sorts  of  flesh  are  alike  in  this  respect ;  the  sapid  and 
odorous  constituents  are   present   in  the  roasted  flesh 
in  solution,  or  in  the  soluble  state.     The  liquid  which  The  flavor  of 
is  obtained  by   lixiviation    of  different   kinds  of  flesh  the^'ifferem 
with  cold  water,  after  it  has  been  heated  to  boiling,  flesh!  ° 
and   the   albumen   thus   coagulated,   possesses,   in   all 
cases,  the  well-known  general  flavor  of  soup ;  but  each 
kind,  individually,  has,  besides  this,  a  peculiar  taste, 
which  recalls  the  taste  and  smell  of  the  different  sorts 
of  flesh  ;  insomuch  that,  when  to  boiled  beef,  for  exam- 
ple, the  concentrated  cold  aqueous  infusion  of  roe-deer  depends  on 
venison  or  of  fowl  is  added,  and  the  whole  warmed  matter. 

*  Note  by  the  Editor.  —  The  Stock  so  much  used  by  good 
cooks,  and  for  preparing  which,  generally  from  beef,  but  often 
also  from  mixed  flesh,  such  minute  directions  are  given  in  books 
on  cookery,  is  essentially  such  a  concentrated  infusion  of  flesh 
as  that  described  in  the  text.  It  is  usually  made  by  long  boiling, 
but  this  is  not  indispensable.  The  addition  of  stock  to  any  dish 
not  only  improves  the  flavor,  but  often  restores  the  soluble  mat- 
ter removed  in  previous  operations,  such  as  boiling,  &c.,  and 
thus  renders  it  much  more  wholesome  and  nutritious  than  it 
would  otherwise  be.  A  good  cook  judges  of  almost  every  thing 
by  the  taste,  and  we  see  in  the  text  the  explanation  of  this, 
since  the  sapid  constituents  are  among  the  most  valuable  parts 
of  the  food.  We  see,  also,  that  in  cookery,  as  in  other  domes- 
tic arts,  long  experience  and  observation  have  led,  in  many  in- 
stances, to  the  most  judicious  practice.  It  is  the  want  of  a  sci- 
entific basis,  however,  for  the  culinary  art,  that  has  given  rise 
to  many  absurd  and  hurtful  methods  of  preparing  food  ;  as,  for 
example,  the  very  common  English  practice  of  boiling  meat  or 
vegetables  with  a  very  large  quantity  of  water,  which  is  thrown 
away,  and  with  it  the  whole,  or  nearly  the  whole,  of  the  solu- 
ble matter.  The  advantage  of  stewing  over  boiling  depends  on 
the  fact,  that  in  the  former  all  the  soluble  matter  is  retained  in 
the  sauce  or  juice,  which  is  served  with  the  meat.  —  W.  G. 


104  FLAVOR    OF    MEAT. 

together,  the  beef  cannot  then  be  distinguished  by  the 

taste  from  the  venison  or  the  fowl.     A  slight  addition 

it  is  height-    of  lactic  acid  (a  very  little  fresh  sauerkraut,  for  ex- 

ened  by  lac- 
tic acid  or  by  ample),  or  of  chloride  of  potassium,  which   is  an   in- 

chloride  of  .       '  L 

potassium,  variable  constituent  of  all  infusions  of  flesh,  heightens 
the  piquancy  of  the  flavor  of  meat ;  as,  on  the  other 
hand,  an  alkaline  liquid,  or  the  addition  of  blood, 
renders  the  soup  or  infusion  of  meat  utterly  insipid 
and  mawkish. 

TheHeshof        From  all  the  different  kinds  of  flesh  we  obtain,  by 

old  animals     .....  .  .  „ 

contains  lit-    lixiviation  with  cold  water,  the  whole  of  the  albumen 

tie  albumen,  ,  .         ..        ,       ,  -r,, 

present  in  them,  in  the  dissolved  state.  The  quantity 
of  coagulated  albumen,  which  separates  from  the  in- 
fusion when  heated,  is  very  different  in  different  speci- 
mens, and  seems  to  stand  in  a  certain  relation  to  the 
age  of  the  animal.  The  flesh  of  old  animals  is  pro- 
portionally poor  in  albumen,  and,  on  the  other  hand, 

but  much  it  is  so  much  the  richer  in  fibrine.  From  the  flesh 
of  an  old  horse,  for  example,  there  was  not  obtained 
the  tenth  part  of  the  quantity  of  albumen  which  was 
furnished  by  an  equal  weight  of  ox-flesh. 

Muscular  The  muscular  fibre,  in  the  natural  state,  is  every- 

where surrounded  by  a  liquid  containing  dissolved  al- 
bumen. When  this  is  removed,  the  fibre,  in  all  ani- 
mals, is  of  the  same  quality.  The  well-washed  mus- 
cular fibre,  when  boiled  with  water,  becomes  hard  and 

its  tender-     horny,  and  this  the  more  the  longer  it  is  boiled.     It 

ness  depends   .  . 

on  the  aibu-    is  obvious,  therefore,  that  the  tenderness  of  boiled  or 

men  of  the  .  .  ./.in 

juice.  roasted  meat  depends  on  the  quantity  of  the  albumen 

deposited  between  the  fibres,  and  there  coagulating ; 
for  the  contraction  or  hardening  of  the  fibrinous  fibres 
is  thereby  to  a  certain  extent  prevented.  This  quali- 
ty, tenderness,  however,  also  depends  on  the  duration 
of  the  boiling ;  for  the  albumen  also  becomes  harder 
by  continued  boiling,  without,  however,  assuming  a 
tough  consistence. 


BEST    METHOD    OF    BOILING    MEAT.  105 

The    influence  of  hot   water    on  the  quality  of  the  Action  of 
meat   which   is  boiled  with   it,   and    of  the    soup    ob-  on  fSier 
tained,  hardly  requires,  after  what  has  been  said,  any 
further  elucidation. 

If  the  flesh  intended  to  be  eaten  be  introduced  into  Best  method 

.  .      .  of  boiling 

the  boiler  when  the  water  is  in  a  state  of  brisk  ebul-  meat. 
lition,  and  if  the  boiling  be  kept  up  for  some  minutes, 
then  so  much  cold  water  added  as  to  reduce  the  tem- 
perature of  the  water  to  165°  or  158°,  and  the  whole 
kept  at  this  temperature  for  some  hours,  all  the  con- 
ditions are  united,  which  give  to  the  flesh  the  quality 
best  adapted  to  its  use  as  food. 

When  it  is  introduced  into  the  boiling  water,  the 
albumen  immediately  coagulates  from  the  surface  in- 
wards, and  in  this  state  forms  a  crust  or  shell,  which 
no  longer  permits  the  external  water  to  penetrate  into 
the  interior  of  the  mass  of  flesh.  But  the  tempera- 
ture is  gradually  transmitted  to  the  interior,  and  there 
effects  the  conversion  of  the  raw  flesh  into  the  state 
of  boiled  or  roasted  meat.  The  flesh  retains  its  juici- 
ness, and  is  quite  as  agreeable  to  the  taste  as  it  can 
be  made  by  roasting ;  for  the  chief  part  of  the  sapid 
constituents  of  the  mass  is  retained,  under  these  cir- 
cumstances, in  the  flesh. 

If  we  reflect  that  the  albumen  of  the  juice  of  flesh  Temperature 
begins  to    coagulate  at  a  temperature  of  105.5°  and 
that  it  is  completely  coagulated  at   140°  (Berzelius), 
it  might  be  supposed  that  it  would  not  be  necessary, 
in  the  cooking  of  flesh,  to  expose  it  to  a  higher  tem- 
perature   than    140°.      But    at    that   temperature    the 
coloring   matter  of  the    blood    is  not  yet  coagulated ; 
the  flesh,  indeed,  is  eatable,  but  when  it  contains  blood, 
it  acquires,   under  these  circumstances,  a  bloody  ap-  underdone 
pearance,  which  it  only  loses,  when  it  has  acquired,  m 
throughout  the  whole  mass,  a  temperature  of  150°  to 
158°. 


106          HOW  TO  OBTAIN  GOOD  SOUP. 

In  the  interior  of  a  very  large  piece  of  flesh,  which 
has  been  boiled  or  roasted,  we  can  tell  with  certainty 
the  temperature  attained  in  the  different  parts,  by  the 
colors  which  they  present.  At  all  those  parts  which 
appear  bloody,  the  temperature  has  not  reached  144°. 
Poultry  is  In  the  boiling  or  roasting  of  poultry,  the  flesh  of  which 

sooner  done      .  .  . 

than  beef  or  is  white,  and  contains  little  blood,  the  temperature  of 
the  inner  parts,  when  the  flesh  has  been  well  cooked, 
seldom  exceeds  130°  or  140°.  The  flesh  of  poultry 
or  game  is  therefore  sooner  dressed  (ready,  or  done 
as  it  is  called)  than  flesh  which  contains  much  blood, 
such  as  beef  or  mutton. 

Use  of  a  By  enveloping  small   pieces  of  flesh    (as    is   often 

covering  of  J 

lard  in  roast-  done  in  the  case  of  small  birds,  such  as  quails,  orto- 
lans, larks,  and  even  partridges)  with  a  covering  of 
lard,  the  extraction  of  the  sapid  constituents  from  the 
flesh  by  its  juices,  and  the  evaporation  of  the  water, 
which  causes  hardening,  are  prevented ;  and  the  sur- 
face, as  well  as  the  subjacent  parts,  is  kept  in  the 
tender  state  which  is  otherwise  only  found  in  the 
inner  portions  of  large  masses  of  flesh. 

HOW  meat  is  The  introduction  of  the  piece  of  raw  flesh  into  water 
to  obtain6  already  boiling  is  the  best  process  for  the  dressing  of 
the  meat,  but  the  most  unfavorable  for  the  quality 
of  the  soup.  If,  on  the  contrary,  the  piece  of  raw 
meat  be  placed  in  cold  water,  and  this  brought  very 
gradually  to  the  boiling  point,  there  occurs,  from  the 
first  moment,  an  interchange  between  the  juices  of 
the  flesh  and  the  external  water.  The  soluble  and 
sapid  constituents  of  the  flesh  are  dissolved  in  the 
water,  and  the  water  penetrates  into  the  interior  of 
the  mass,  which  it  extracts  more  or  less  completely. 
The  flesh  loses,  while  the  soup  gains,  in  sapid  matters ; 
and,  by  the  separation  of  albumen,  which  is  commonly 
removed  by  skimming,  as  it  rises  to  the  surface  of 


GELATINE  NOT  THE  SOURCE  OF  STRENGTH  OF  SOUP.  107 

the  water  when  coagulated,  the  surface  of  the  meat 
more  particularly  loses  its  tenderness  and  shortness 
(as  it  is  called),  becoming  tough  and  hard.  The  thin-  Meat  from 

which  soup 

ner  the  piece  of  flesh,  the  more  completely  does  it  ac-  has  been 

r .    .     *  made  is  nei- 

quire  the  last-mentioned  qualities  ;  and  if  in  this  state  ther  nutri- 
tious nor  di- 
it  be  eaten  without  the  soup,  it  not  only  loses  much  of  gestibiewith- 

,  „.,.......  out  the  soup. 

its  nutritive  properties,  but  also  of  its  digestibility,  inas- 
much as  the  juice  of  the  flesh  itself,  the  constituents  of 
which  are  now  found  in  the  soup,  is  thus  prevented 
from  taking  part  in  the  digestive  process  in  the  stom- 
ach. The  soup,  in  fact,  contains  two  of  the  chief  con- 
stituents of  the  gastric  juice. 

It  has  long  been  customary  to  ascribe  to  the  gelat-  Gelatine  i* 
inous  matter  dissolved  during  boiling,  which  gives  to  »oore«of 
concentrated  soup  the  property  of  forming  a  jelly,  the  ^flavor  ofh 
chief  properties  or  peculiarities  of  the  soup  ;  but  there  soup' 
cannot  be  a  greater  mistake.      The  simplest  experi- 
ments prove  that  the  amount  of  dissolved  gelatine  in 
well-prepared  soup  is  so  small,  that  it  cannot  come  into 
calculation  in  explaining  its  properties.     Gelatine  is,  in 
itself,  quite  tasteless,  and  consequently  the  taste  of  the 
soup  cannot  be  derived  from  it. 

In  order  to  determine  the  amount  of  gelatinous  mat-  Experiment* 
ter  dissolved  in  the  boiling  of  flesh  under  the  most  fa-  the  amount 
vorable  circumstances,  finely  chopped  meat  was  ex-  disfoi*e<?hi 
hausted  with  cold  water,  pressed  as  dry  as  possible,  I3*j£j?°* 
and  the  residue,  fibres  and  membranes,  boiled  for  five 
hours  with  ten  times  its  weight  of  water,  the  liquid 
pressed  out  from  the  insoluble  matter,  and  evaporated 
to  dry  ness  in  the  water-bath.     The  soup  thus  obtained, 
from  beef  and  veal,  was  tasteless,  or  rather  had  a  pe- 
culiar mawkish  taste,  which  to  most  persons  was  nau- 
seous.    That  from   veal   gelatinized  when  reduced  to 
half,  that  from  beef  when  reduced  to  ^th,  of  its  original 
volume. 


108  BEST    METHOD    CF    PREPARING 

3,000  grammes  of  lixiviated  veal  (6  Ibs.)  yielded, 
under  these  circumstances,  after  five  hours'  boiling, 
47.5  gms.  of  matter  dissolved  by  the  water  (gelatine, 
&c.). 

1,000  gms.  of  lixiviated  beef  (2  Ibs.)  yielded,  in  the 
same  way,  6  gms.  of  gelatine,  &c. 

It  appears  from  these  experiments,  that  the  muscular 
fibres  and  membranes  of  the  calf  and  ox,  in  that  state 
in  which  they  present  to  the  dissolving  energy  of  the 
water  the  largest  surface,  and  after  five  hours'  boiling, 
yielded,  the  former  only  1.576  per  cent.,  the  latter  0.6 
per  cent.,  of  soluble  matter,  of  which  the  gelatine  cer- 
tainly does  not  constitute  one  half,  since  some  part  or 
constituent  of  the  fibrine  is  also  dissolved  under  these 
circumstances. 

Those  constituents  of  1,000  gms.  or  2  Ibs.  of  beef, 
which  are  soluble  in  cold  water,  weighed,  when  dry, 
60  gms.,  of  which  29.5  gms.  were  albumen. 
A  mount  of         Under  the  most  favorable  circumstances,  therefore, 
LoiiSffcL    we  obtain>  from  1'000  gms-  of  beef> 


_    C  Coagulated  Albumen  .        29.5 
Soluble  in  cold  water  60  $  T 

C  In  the  solution         .         .     30.5 

....  C  Gelatine       .         .         .  6.0 

Insoluble  in  cold  water        170  <  „.,         ,,      ,  e         .,-.  A 

(  Fibres,  Membranes,  &c.     154.0 

Fat       ....  20 

Water     ....     750 

1000 

It  follows,  that  boiling  water,  when  allowed  to  act 
for  five  hours  on  finely  chopped  flesh,  does  not  dis- 
solve more  than  the  fifth  part  of  the  matters  soluble  in 
cold  water,  even  after  the  albumen  has  been  separated 
by  heating  the  cold  infusion ;  and  that  this  fifth  part 
does  not  consist  of  pure  gelatine,  but  contains  all  the 
products  dissolved  out  of  the  muscular  fibres  by  long 
boiling. 


SOUP    FROM    FLESH.  109 

Consequently  the  efficacy  of  soup,  or  decoction  of 
flesh,  cannot  depend  on  the  gelatine  it  contains. 

The   flesh  of   poultry   contains,   for  equal  weights,  More  soluble 
more  of  the  matters  soluble  in  cold  water,  and  remain-  poultry  than 
ing   dissolved  after    the  coagulation  of   the  albumen, 
than  beef  does. 

From  1,000  gms.  of  fowl,  cold  water  takes  up  80 
gms.  of  soluble  matter,  of  which  47  gms.  consist  of 
albumen,  and  33  gms.  remain  dissolved  in  the  liquid 
when  boiled. 

The  characters  of  flesh  described  in  the  preceding  The  nutri- 
paragraphs  at  once  suggest  the  best  method  of  prepar-  pid  ingradi- 
ing,  in  the  short  space  of  a  few  minutes,  the  strongest  exist  ready1  P 
and  most  highly  flavored  soup  ;  and  any  one  may  con-  fl°eshe 
vince  himself,  by  the  simplest  experiments,  of  the  truth 
of  the  assertion  made  by  Proust,  that  those  constituents 
of  soup,  on  which  its  taste  and  other  properties  depend, 
exist  ready  formed  in  the  flesh,  and  are  not  in  any  way 
products  of  the  operation  of  boiling. 

When  1  Ib.  of  lean  beef,  free  of  fat,  and  separated  Best  method 

...     .     of  preparing 

from  the  bones,  in  the  finely  chopped  state  in  which  it  soup, 
is  used  for  beef  sausages  or  mince- meat,  is  uniformly 
mixed  with  its  own  weight  of  cold  water,  slowly  heated 
to  boiling,  and  the  liquid,  after  boiling  briskly  for  a 
minute  or  two,  is  strained  through  a  towel  from  the 
coagulated  albumen  and  the  fibrine,  now  become  hard 
and  horny,  we  obtain  an  equal  weight  of  the  most 
aromatic  soup,  of  such  strength  as  cannot  be  obtained, 
even  by  boiling  for  hours,  from  a  piece  of  flesh.  When 
mixed  with  salt  and  the  other  usual  additions,  by  which 
soup  is  usually  seasoned,  and  tinged  somewhat  darker 
by  means  of  roasted  onions  or  burnt  sugar,  it  forms  the 
very  best  soup  which  can  in  any  way  be  prepared  from 
1  Ib.  of  flesh. 

The  influence  which  the  brown  color  of  this  soup,  influence  of 
^  the  brow  a 


110  PORTABLE    SOUP. 

color  of  soup  or  color  in  general,  exercises  on  the  taste,  in  conse- 
ment  we"  °   quence  of  the  ideas  associated  with  color  in  the  mind 

form  as  to        / .  ,  «  x 

its  strength  (ideas  oi  strength,  concentration,  &c.),  may  be  ren- 
dered quite  evident  by  the  following  experiment.  The 
soup,  colored  brown  by  means  of  caramel,  is  declared 
by  all  persons  to  have  a  much  stronger  taste  than  the 
same  soup  when  not  colored  ;  and  yet  the  caramel, 
in  point  of  fact,  does  not  in  any  way  actually  heighten 
the  taste. 

If  we  allow  the  flesh  to  boil  for  a  long  time  with  the 

.«  ,     .,     ,  . 

water,  or  if  we  boil  down  the  soup,  it  acquires,  spon- 
taneously, when  concentrated  to  a  certain  point,  a 
brownish  color  and  a  delicate  flavor  of  roast  meat.  If 
we  evaporate  it  to  dry  ness  in  the  water-bath,  or  if  pos- 
sible at  a  still  lower  temperature,  we  obtain  a  dark 
brown,  soft  mass,  of  which  half  an  ounce  suffices  to 
convert  1  Ib.  of  water,  with  the  addition  of  a  little  salt, 
into  a  strong,  well-flavored  soup. 

^e  tablets  °?  so-called  portable  soup,  prepared  in 

ikSnePure  England  and  France,  are  not  to  be  compared  with  the 
extract  of  flesh  just  mentioned  ;  for  these  are  not  made 
from  flesh,  but  consist  of  gelatine,  more  or  less  pure,  on- 
ly distinguished  from  bone  gelatine  by  its  higher  price.* 

Beef  yields         From  32  Ibs.  of  lean  beef,  free  from  bones  and  fat 

weight  of  ex-  (8  Ibs.  dry  meat  and  24  Ibs.  water),  there  is  obtained  1 
Ib.  of  true  extract  of  flesh,  which,  from  its  necessarily 
high  price,  can  hardly  become  an  article  of  commerce ; 
but  if  the  experience  of  military  surgeons  agrees  with 

Extract  of      that  of  Parmentier,   according  to   whom    "The   dried 

meat   recom-  .  .... 

mended  as  a  extract  of  flesh,  as  an  article  of  provision  in  the  tram 
for  wounded    of   a  body  of  troops,    supplies    to   severely  wounded 

soldiers.  

*  Note  by  the  Editor.  —  I  have  seen  some  specimens  of  porta- 
ble soup,  which,  although  consisting  chiefly  of  gelatine,  yet  had 
a  strong  flavor  of  soup,  and  probably,  therefore,  contained  a  cer- 
tain proportion  of  extract  of  flesh.  —  W.  G. 


SALTING   MEAT.  Ill 

soldiers  a  restorative,  or  roborant,  which,  with  a  little 
wine,  immediately  revives  their  strength,  exhausted  by 
great  loss  of  blood,  and  enables  them  to  bear  the  trans- 
port to  the  nearest  hospital,"  *  it  appears  to  me  to 
be  a  matter  of  conscience  to  recommend  to  the  atten- 
tion of  governments  the  proposal  of  Parmentier  and  of 
Proust. 

Now  that  the  composition  of  the  extract  of  flesh  is  Characters  of 

,      ,  .  genuine  and 

somewhat  more  accurately  known,  it  ought  to  be  easy  of  false  ex 
for  every  well-informed  apothecary  to  distinguish  the 
genuine  from  the  false.  Of  the  true  extract,  nearly  80 
per  cent,  is  soluble  in  alcohol  of  85  per  cent.,  while 
the  ordinary  tablets  of  portable  soup  rarely  yield  to 
that  menstruum  more  than  4  or  5  per  cent.  The 
presence  of  kreatine  and  kreatinirie,  the  latter  of  which 
is  instantly  detected  by  the  addition  of  chloride  of  zinc 
to  the  alcoholic  solution,  as  well  as  the  nature  of  the 
salts  left  on  incineration,  which  chiefly  consist  of  solu- 
ble phosphates,  furnishes  sufficient  data  for  judging  of 
the  quality  of  the  true  extract  of  flesh. 

I  consider  this  extract  of  flesh  as  not  less  valuable  Extract  of 

.  .  meat  recom- 

ior  the  provisioning  of  ships  and  fortresses,  in  order  to  mended  for 
preserve  the  health  of  the  crew  or  garrison,  in  those  fortresses,  a* 

.  .  an  addition 

cases  where   fresh  meat  and  vegetables  are  wanting,  to  salt  meat. 
and  the  people  are  supported  by  salt  meat. 

It  is  universally  known,  that,  in  the  salting  of  meat,  Salting  of 

meat, 

the  flesh  is  rubbed  and  sprinkled  with  dry  salt,  and  that 
where  the  salt  and  meat  are  in  contact,  a  brine  is 
formed,  amounting  in  bulk  to  ^d  of  the  fluid  contained 
in  the  raw  flesh. 

I  have  ascertained  that  this  brine  contains  the  chief  The  brine  of 
constituents  of  a  concentrated  soup  or  infusion  of  meat, 


*  See  Proust,  Annales  de  Chimie  et  de  Physique.     Third  Se- 
ries, Vol.  XVIII.  p.  177. 


112 


EFFECTS    OF    SALTING. 


ingredients 
of  the  ex- 
tract ; 


phosphates, 
lactic  acid, 
kreatine,  and 


kreatinine. 


Salted  meat 
is  deficient 
in  nutritive 
quality. 


Causes  of 
this. 


and  that,  therefore,  in  the  process  of  salting,  the  com- 
position of  the  flesh  is  changed,  and  this,  too,  in  a 
much  greater  degree  than  occurs  in  boiling.  In  boil- 
ing, the  highly  nutritious  albumen  remains  in  the  coag- 
ulated state  in  the  mass  of  flesh,  but  in  salting,  the  al- 
bumen is  separated  from  the  flesh  ;  for  when  the  brine 
from  salted  meat  is  heated  to  boiling,  a  large  quantity 
of  albumen  separates  as  a  coagulum.  This  brine  has 
an  acid  reaction,  and  gives  with  ammonia  a  copious 
precipitate  of  the  double  phosphate  of  ammonia  and 
magnesia.  It  contains  also  lactic  acid,  a  large  quantity 
of  potash,  and  kreatine,  which,  although  I  could  not 
separate  that  body  from  the  large  excess  of  salt,  may 
be  safely  concluded  to  be  present,  from  the  presence  of 
kreatinine.  The  brine,  when  neutralized  by  lime,  gives, 
after  the  salt  has  been  crystallized  out,  a  mother  liquid, 
from  which,  after  some  time,  when  alcohol  and  chlo- 
ride of  zinc  are  added  to  it,  the  double  chloride  of  zinc 
and  kreatinine,  so  often  mentioned  in  the  former  part 
of  this  work,  is  deposited. 

It  is  now  easy  to  understand  that  in  the  salting  of 
meat,  when  this  is  pushed  so  far  as  to  produce  the 
brine  above  mentioned,  a  number  of  substances  are 
withdrawn  from  the  flesh,  which  are  essential  to  its 
constitution,  and  that  it  therefore  loses  in  nutritive 
quality  in  proportion  to  this  abstraction.  If  these  sub- 
stances be  not  supplied  from  other  quarters,  it  is  obvi- 
ous that  a  part  of  the  flesh  is  converted  into  an  element 
of  respiration  certainly  not  conducive  to  good  health. 
It  is  certain,  moreover,  that  the  health  of  a  man  cannot 
be  permanently  sustained  by  means  of  salted  meat,  if 
the  quantity  be  not  greatly  increased,  inasmuch  as  it 
cannot  perfectly  replace,  by  the  substances  it  contains, 
those  parts  of  the  body  which  have  been  expelled  in 
consequence  of  the  change  of  matter,  nor  can  it  pre- 


>  EFFECTS    OF    SALTING.  113 

serve  in  its  normal  state  the  fluid  distributed  in  every 
part  of  the  body,  namely,  the  juices  of  the  flesh.  A 
change  in  the  quality  of  the  gastric  juice,  and  conse- 
quently in  that  of  the  products  of  the  digestive  process, 
must  be  regarded  as  an  inevitable  result  of  the  long- 
continued  use  of  salted  meat ;  and  if  during  digestion 
the  substances  necessary  to  the  transformation  of  that 
species  of  food  be  taken  from  other  parts  of  the  organ- 
ism, these  parts  must  lose  their  normal  condition. 

In  my  experiments  on  the  salting  of  meat,  I  used  at  Effects  pro- 
first  a  species  of  salt  which  subsequently  proved,  on  meat  by  salt 
examination,  to  contain  a   considerable    proportion  of  ^ofiSeaof 
chloride  of  calcium  and  chloride  of  magnesium.     I  was  magnesium, 
induced  to  examine  the  salt  by  observing  that  the  brine 
obtained  from  meat  salted  with  it  contained  only  traces 
of  phosphoric  acid.     The  external  aspect  of  the  salted 
flesh  sufficiently  explained  this  unexpected  fact ;  for  it 
was  covered  as  if  with  a  white  froth,  consisting  chiefly 
of  phosphate  of  lime  and  phosphate  of  magnesia.     The 
earthy  salts  of  the  sea  salt  had  entered  into  mutual  de- 
composition with  the  alkaline  phosphates  of  the  juice, 
producing  phosphates  of  lime  and  magnesia,  of  which 
only  very  small  quantities  could  be  dissolved  in  the  acid 
brine. 

In  the  use  of  a  salt  rich  in  lime  and  magnesia,  there  Meat  thus 
may  thus  be  a  cause  which  renders  the  meat  salted  with  be  iess"un^ 
it  less  injurious  to  the  system.     For  it  is   plain,  that  w 
when,  along  with  such  meat,  vegetables  are  eaten  which 
are  rich  in  potash  (and  this  is  the  case  with  all  esculent 
vegetables),  the  conditions  are  present  which  determine 
the  reproduction,  during  digestion,  of  the  deficient  alka- 
line phosphates.     That  these  latter  salts  may  actually 
be  formed  under  such  circumstances  is  shown  by  the 
analysis  of  milk,  a  fluid  rich  in  alkaline  phosphate,  corn- 
pared  with  that  of  the  fodder  or  food  of  graminivorous 
10* 


114  LACTIC    ACID    IN    THE    GASTRIC    JUICE. 

animals,  which  last  contains  no  alkaline  phosphates, 
but  phosphates  of  lime  and  magnesia  along  with  salts 
of  the  alkalies,  with  other  acids. 

When  we  compare  flesh  with  other  animal  food,  such 
as  eggs  and  cheese,  the  difference  is  striking,  and  the 
difficult  digestibility  of  the  latter,  when  compared  with 
flesh,  unquestionably  depends  on  the  difference  in  their 
composition. 

The  soluble        If  we  consider  that  the  juice  of  flesh,  in  all  ani- 
of  the  mSss    mals  yet  examined,  possesses  a  constant  character  ;  that, 
essenTiaf  to    exclusive  of  those  constituents  which  are  derived  from 
MOM.  *       the  blood  unavoidably  mixed  with  it,  as  well  as  of  small 
quantities  of  odorous  and  sapid  substances  on  which  the 
characteristic  secondary  or  by-taste  of  the  juice  or  soup 
of  the  flesh  in  each  kind  of  animal  depends,  the  juice 
of  ox-flesh  is  in  no  way  distinguishable  from  that  of  the 
fox,  it  seems  justifiable  to  conclude  that  the  quantity  and 
the  nature  of  the  soluble  constituents  in  the  muscular 
system  are  essential  to  the  functions  of  the  muscles. 
It  appears  further  to  follow,  that,  in  judging  of  the  nu- 
tritive  qualities  of  any  kind  of  food,  the  composition 
of  the  blood  cannot  be  selected  as  the  proper  datum 
from  which  to  argue,  because  there  are  a  number  of 
factors  which  must  be  brought  into  the  calculation,  and 
which  are  either  wanting  in  the  blood,  or  present  in  it 
only  in  trifling  quantity. 
Lactic  acid         Some  experiments  have  lately  been  made  by  Leh- 

found  in  the  ... 

gastric  juice  mann  on  the  gastric  juice  of  dogs,  fed  on  bones  and 
Lehman  n.  lean  horse-flesh,  which  fluid  he  has  studied  more  mi- 
nutely than  had  previously  been  done.  He  obtained 
from  it  a  crystallized  salt  of  magnesia,  combined  with 
an  organic  acid,  not  containing  nitrogen.  This  salt 
yielded  16.6  p.  c.  of  magnesia,  and  21  p.  c.  of  water  of 
crystallization.  Now  that  we  know  that  lactic  acid 
forms  a  constituent  of  the  chief  mass  of  the  body,  it  is 


VOLATILE    ACIDS    OF    GASTRIC    JUICE.  115 

evident  that  Lehmann's  magnesian  salt,  which  agrees 
with  lactate  of  magnesia  in  the  proportion  of  base  and 
of  water  of  crystallization,  really  was  lactate  of  mag- 
nesia.    In  that  case,  the   gastric  juice  contains  lactic  The  digest- 
acid,  and  thus  the  problem  of  the  digestive  process  in  jn^ 
the  stomach  would  appear,  in  its  chemical  aspect,  to  be 
completely  solved. 

The  experiments  of  all  who  have  studied  the  gastric  The  gastric 
juice  agree  in  this,  that  that  fluid  contains,  along  with  to'the^uice^ 
an  organic  acid,  free  phosphoric  acid  or  an  acid  phos- 
phate, and  in  this  respect  its  similarity  with  the  juice  of 
the  muscles  is  strikingly  obvious.     That  portion  of  the 
gastric  juice  which  is  soluble  in  alcohol  is,  in  its  reac- 
tion, identical  with  the  alcoholic  extract  of  soup,  as 
Tiedemann  and  Gmelin  have  already  shown ;  and  the 
soup  or  infusion  of  meat,  free  from  gelatine  and  fat,  the 
preparation  of  which  I  have  described  (ante,  p.  109),  The  soup 
may  perhaps  admit  of  being  employed  as  a  valuable  scribed  pro3" 
remedy  for  many  dyspeptic  patients,  with  a  view  to  in-  remedy8in 
creasing  the  activity  of  the  stomach,  and  promoting  di-    ysp 
gestion.    Again,  if  the  blood  or  the  muscular  substance 
of  emaciated  convalescents  cannot  supply  the  matters 
necessary  for  digestion  in  sufficient  quantity  for  a  rapid 
reproduction  of  the  lost  strength  (that  is,  the  lost  parts 
of  the  organism)  the  benefit  derived  from  well-made  its  value  to 
soup  during  convalescence  admits  of  a  simple  explana-  cents! es' 
tion. 

Finally,  when  we  recollect  that  lactic  and  phosphoric  origin  of  the 
acids,  at  temperatures  in  which  hydrochloric,  acetic,  andotter"0 
and  butyric  acids  are  volatilized,  are  almost  fixed,  we  obtained^  * 
can  explain  how  it  happens  that  in  many  cases  hydro- 
chloric  acid,  in  others  acetic  or  butyric  acid,  has  been 
obtained  by  distilling  the  gastric  juice.  Acetates,  buty- 
rates,  arid  even  chloride  of  sodium,  are  decomposed  by 
lactic  acid,  as  well  as  by  acid  phosphates,  in  these  circum- 


116  THE    SUBJECT    NOT    EXHAUSTED. 

stances,  and  the  occurrence  of  the  one  or  the  other  of 
the  more  volatile  acids  must  vary  with  the  amount  of 
the  lactic  or  phosphoric  acid  present  in  the  gastric 
juice,  and  the  amount  also  of  their  salts  in  the  same 
fluid. 


CONCLUSION. 

These  re-  I  THINK  it  right  to  state,  distinctly,  that  I  am  far  from 

searches  only  -  •>      •  T 

the  com-        considering  the  nature  and  quality  of  the  substances  oc- 

mencement  .....  «   n      .  «  „  ,  ,         , 

of  a  more       curnng  in  the  juice  of  flesh  as  fully  ascertained  by  the 

complete  in-     .  .  ,  .       ,  ,. 

vedtigation.  investigation  contained  in  the  preceding  pages.  On  the 
contrary,  I  am  of  opinion,  that  it  ought  only  to  be  re- 
garded as  the  commencement  of  a  more  complete  work. 
But  the  minute  study  and  thorough  investigation  of  those 
substances  contained  in  that  fluid,  which  have  not  yet 
been  studied,  demand  so  much  time,  that  I  did  not 
wish  to  delay  the  publication  of  the  results  hitherto  ob- 
tained till  the  completion  of  my  researches. 

Various  sub-      Of  the  tissue  called  muscular,  fibrine  and  albumen 

distinguish-    are  the  chief  constituents  in  fully  developed  animals. 

muscular  This  tissue  is  everywhere  interwoven  with  delicate  mem- 
branes, and  a  number  of  minute  vessels  are  ramified 
throughout  it,  which  are  filled,  partly  with  colored,  part- 
ly with  colorless  fluids.  No  other  part  of  the  body  ab- 
sorbs so  large  a  part  of  the  nervous  system.  As  Ber- 
zelius  points  out,  we  must  distinguish  fibrine,  albumen, 
and  cellular  tissue,  partly  organized,  partly  in  the  state 
adapted  for  their  conversion  into  organized  structure ; 
and,  lastly,  we  have  in  the  fluids  these  substances  in  the 
effete  state,  or  in  the  condition  best  adapted  for  their 
removal.  We  have  also  to  distinguish  the  colored  and 
colorless  fluids  brought  to  the  muscle  in  the  vessels ; 


SUBSTANCES    IN    FLESH   NOT    YET    STUDIED.         117 

arid  the  membranes  of  the  distributed  nerves,  as  well  as 
the  substance  itself  of  those  nerves. 

When  analysis  shall  have  become  so  perfect  as  to  en-  Province  of 

..„  .  chemical 

able  us  to  separate  these  different  substances  in  a  ra-  analysis, 
tional  manner,  she  will  have  fulfilled  her  duty.  At 
present,  analysis  begins  by  mixing  them  altogether,  and 
a  chemical  result  is  obtained,  which  gives  room  for  a 
multitude  of  questions.  These  questions  are,  in  the 
present  state  of  our  knowledge,  the  conditions  of  fur- 
ther progress. 

Kreatinine  and  kreatine  are  constituents  of  the  mus-  Kreatine  and 

.  kreatinine 

cles,  but  they  are  also  constituents  of  urine  ;  and  if  any  occur  both  m 

,.    .           1,1  i  i     •  muscle  and 

process  in  the  living  body  depends  upon  their  pres-  in  urine. 
ence,  it  is  evident  that  only  that  portion  of  these  two 
compounds  can  pass  into  the  urine,  which  has  not  been 
employed  for  vital  purposes.  The  examination  of  the 
urine  in  diseases  will  probably  very  soon  shed  light  on 
this  question. 

That  portion  of  the  juice  of  flesh  which  is  soluble  in  Gelatinous 
cold  water,  but  not  in  alcohol,  possesses  all  the  proper-  ^c^offlUh* 
ties  of  gelatine,  except  that  of  gelatinizing  when  con- 
centrated.    It  is  precipitated  by  tannic  acid  ;  the  pre- 
cipitate softens  like  plaster  in  hot  water,  and  cannot  be 
distinguished  from  the  tannate  of  gelatine  by  its  aspect. 

A  second  substance,  which  I  have  not  yet  further  in-  Another  sub- 

,      .  .  .  «    Al       stance  in  the 

vestigated,  separates,    during   the    evaporation  of   the  juice  of  flesh, 
juice  of  flesh,  in  the  form  of   a  skin  or  membrane, 
which  no  longer  dissolves  in  cold  water,  but  swells  .up 
and  becomes  mucilaginous.     It  is  not,  as  might  be  im- 
agined, caseine. 

Of  the  substances  soluble  in  alcohol,  the  greater  part  Unknown  m- 
consists  of  one  or  probably  of  more  bodies,  particularly  bodies1^  the 

•    i    •  it  „!  t    A  i  •    i         f        juice  of  flesh. 

rich  in  nitrogen  ;  these  are  the  substances,  which,  after 
the  phosphoric  acid  has  been  removed,  give  rise,  on  in- 
cineration of  the  residue,  to  so  great  a  mass  of  cyanide 
of  potassium. 


118       NO  UREA  IN  THE  JUICE  OF  FLESH. 

New  acid  in        When  that  part  of  the  juice  of  flesh  which  is  soluble 

the  juice  of      .  .  ... 

flesh,  not  yet  m  alcohol  and  in  ether  is  mixed  with  sulphuric  acid,  to 
separate  the  alkali,  and  the  filtered  liquid  is  left  at  rest 
for  some  days,  there  are  deposited  long  transparent  col- 
orless needles,  which  have  a  strong  acid  reaction  and 
contain  no  alkali.  I  first  noticed  this  substance  at  the 
close  of  this  investigation,  and  obtained  too  small  a 
quantity  to  enable  me  to  analyze  it. 

Another  ni.         Lastly,  if  the  acid  liquid  thus  obtained  be  saturated 

trogenized  .... 

acid  in  flesh,  with  lime,  evaporated  to  dry  ness,  and  the  residue  washed 
with  alcohol,  the  addition  of  ether  to  the  alcohol  causes 
a  deposit ;  and  the  liquid  separated  from  this  contains 
kreatinine,  combined  with  an  organic  acid,  rich  in  nitro- 
gen, which  I  have,  in  like  manner,  not  yet  more  mi- 
nutely examined. 

Urea  not  I  have  taken  the  utmost  pains  to  detect  urea  or  uric 

juice  of  flesh,  acid  in  the  juice  of  flesh,  and  I  believe  that  I  should 
have  succeeded  in  doing  so,  even  had  no  more  than 
one  millionth  part  of  these  substances  been  present. 
According  to  my  experiments,  therefore,  urea  is  not  a 

Uric  acid  constituent  of  the  juice  of  flesh.  In  one  case  only, 
where  I  had  added  chloride  of  barium  to  the  alcoholic 
solution  of  the  extract  of  flesh,  crystalline  flocculi  sep- 
arated after  exposure  for  weeks  in  the  air.  These  were 
not  dissolved  by  hot  water  or  in  hydrochloric  acid,  but 
dissolved  in  nitric  acid,  with  disengagement  of  red 
fumes,  exactly  like  uric  acid ;  and  the  solution  gave 
with  ammonia  the  same  purple  color  which  uric  acid 
would  have  given  in  like  circumstances.  This  sub- 
stance, however,  I  have  not  been  able  again  to  pro- 
cure. 


ADDENDUM. 


NOTE    BY    THE    EDITOR. 

FROM  the  mother  liquor  which  had  deposited  the 
kreatine  which  I  prepared,  and  which  contained  the 
soluble  matter  of  nearly  7  Ibs.  of  fowl,  I  obtained, 
by  the  process  indicated  at  p.  63,  by  the  author,  4 
grammes,  or  about  61  grains,  of  pure  and  well-crystal- 
lized inosinate  of  baryta.  It  is  certain  that  I  did  not 
succeed  in  obtaining  the  whole  of  the  inosinic  acid 
originally  present  in  the  juice ;  but  the  above  quantity 
was  procured  without  difficulty  ;  and  it  would  therefore 
appear  that  in  fowl,  at  least,  the  quantity  of  inosinic 
acid  is  not  so  small  or  insignificant  as  the  author  seems 
to  think. 


TABLE 

SHOWING    THE    PROPORTION     BETWEEN    THE    ENGLISH    AND    HES- 
SIAN   STANDARD    OF    WEIGHTS    AND    MEASURES. 

1  lb.  English  is  equal  to  0.90719  Ib.  Hessian. 

1  Hessian  acre  is  equal  to  26,910  English  square  feet. 

1  English  square  foot  is  equal  to  1.4864  Hessian  square  feet. 

1  English  cubic  foot  contains  1.81218  Hessian  cubic  feet. 


RESEARCHES 


MOTION    OF    THE    JUICES 


THE    ANIMAL    BODY. 


11 


PREFACE 

TO    THE    ENGLISH    EDITION. 


IN  (he  Editor's  Preface  to  Baron  Liebig's  "  Re- 
searches on  the  Chemistry  of  Food,"  in  which 
the  author  gave  the  results  of  his  investigation 
into  the  constituents  of  the  juice  of  flesh,  I  men- 
tioned that  Baron  Liebig  had  been  led  to  study 
the  subject  of  Endosmosis  experimentally.  The 
results  of  this  investigation  are  contained  in  the 
following  pages  ;  and  the  reader  will,  I  trust,  be 
satisfied  that  the  motions  of  the  animal  juices 
depend  on  something  more  than  mere  Endosmosis 
or  Exosmosis,  and  that  the  pressure  of  the  atmos- 
phere, as  well  as  its  hygrometric  state,  by  influ- 
encing the  transpiration  from  the  skin  and  lungs, 
is  essentially  concerned  in  producing  these  mo- 
tions. At  the  same  time,  the  present  work  is  to 
be  regarded,  not  as  exhausting  the  subject,  but, 
on  the  contrary,  as  only  pointing  out  the  direction 
in  which  inquiry  is  likely  to  lead  to  the  most 
valuable  results. 


124  PREFACE    TO    THE    ENGLISH    EDITION. 

While  it  is  proved  that  the  mechanical  causes 
of  pressure  and  evaporation,  and  the  chemical 
composition  of  the  fluids  and  membranes,  have  a 
more  direct,  constant,  and  essential  influence  on 
the  motion  of  the  animal  fluids,  and  consequently 
on  the  state  of  the  health,  than  has  been  usually 
supposed,  it  is  evident  that  very  much  remains 
to  be  done  in  tracing  that  influence  under  the 
ever  varying  circumstances  of  the  animal  body, 
and  in  applying  the  knowledge  thus  acquired  to 
the  purposes  of  hygiene  and  therapeutics.  But 
it  is  equally  obvious,  that  the  above-mentioned 
mechanical  and  chemical  causes  are  not  alone  suf- 
ficient "  to  explain  the  phenomena  of  animal  life, 
since  they  are  present  equally  in  a  dead  and  in 
a  living  body  ;  so  that  while  every  advance  in 
physiology  enables  us  to  explain  more  facts  on 
chemical  and  mechanical  principles,  something  al- 
ways remains,  which,  for  the  present,  is  beyond 
our  reach,  and  which  may  for  ever  remain  so. 
However  this  may  be,  the  facts  established  in  this 
and  in  the  preceding  work  of  the  author  have  very 
materially  extended  the  application  of  the  well- 
known  laws  of  physics  and  of  chemistry  to  physi- 
ology, and  have  also  furnished  a  number  of  the 
most  beautiful  instances  of  that  infinitely  wise, 
but  exquisitely  simple,  adaptation  of  means  to  ends 
which  characterizes  all  the  works  of  the  omnipo- 
tent Creator ;  but  which  is  nowhere  more  admira- 


PREFACE    TO    THE    ENGLISH    EDITION.  125 

bly  displayed  than  in  the  arrangements,  imperfect- 
ly known  as  they  hitherto  have  been,  by  which 
life  is  maintained. 

In  connection  with  the  author's  remarks  on  the 
effects  of  evaporation  in  plants,  and  the  conse- 
quences of  its  suppression,  and  with  his  opinions 
as  to  the  origin  of  the  potato  disease,  I  beg  to 
refer  the  reader  to  the  Appendix  for  a  very  in- 
genious arid  apparently  well-founded  plan  for  the 
protection  of  the  potato-plant  against  the  terrible 
scourge  under  which  it  has  lately  suffered.  The 
views  of  Dr.  Klotzsch,  the  author  of  this  plan, 
as  to  the  nature  of  the  disease,  coincide  remarka- 
bly with  those  of  Baron  Liebig,  as  explained  in 
the  present  work. 

WILLIAM   GREGORY. 

EDINBURGH,  3d  March,  1848. 


11 


PREFACE. 


THE  present  little  work  contains  a  series  of  ex- 
periments, the  object  of  which  is  to  ascertain  the 
law  according  to  which  the  mixture  of  two  liquids, 
separated  by  a  membrane,  takes  place.  The  read- 
er will,  I  trust,  perceive  in  these  researches  an 
effort  to  attain,  experimentally,  to  a  more  exact 
expression  of  the  conditions  under  which  the  ap- 
paratus of  the  circulation  acquires  all  the  proper- 
ties of  an  apparatus  of  absorption. 

In  the  course  of  this  investigation,  the  more 
intimate  study  of  the  phenomena  of  Endosmosis 
impressed  on  me  the  conviction,  that,  in  the  or- 
ganism of  many  classes  of  animals,  causes  of  the 
motion  of  the  juices  were  in  operation  far  more 
powerful  than  that  to  which  the  name  of  Endos- 
mosis has  been  given. 

The  passage  of  the  digested  food  through  the 
membranes  of  the  intestinal  canal,  and  its  entrance 
into  the  blood ;  the  passage  of  the  nutrient  fluid 
outwards  from  the  bloodvessels,  and  its  motion 
towards  the  parts  where  its  constituents  acquire 


128  PREFACE. 

vital  properties,  —  these  two  fundamental  phenom- 
ena of  organic  life  cannot  be  explained  by  a  sim- 
ple law  of  mixture. 

The  experiments  described  in  the  following 
pages  will,  perhaps,  be  found  to  justify  the  con- 
viction, that  these  organic  movements  depend  on 
transpiration  and  atmospheric  pressure. 

The  importance  of  transpiration  for  the  nor- 
mal vital  process  has  indeed  been  acknowledged 
by  physicians  ever  since  medicine  had  an  exist- 
ence ;  but  the  law  of  the  dependence  of  the  state 
of  health  on  the  quality  of  the  atmosphere,  on  its 
barometric  pressure,  and  its  hygrometric  condition, 
has  been  hitherto  but  little  investigated. 

By  the  researches  contained  in  my  examination 
of  the  constituents  of  the  juice  of  flesh,  as  well 
as  by  those  described  in  the  present  work,  the 
completion  of  the  second  part  of  my  Animal 
Chemistry  has  been  delayed  ;  but  I  did  not  con- 
sider myself  justified  in  continuing  that  work  until 
I  had  examined  the  questions  suggested  by  and 
connected  with  those  researches. 

DR.  JUSTUS   LIEBIG. 

GIESSEN,  February,  1848. 


ON    THE    PHENOMENA 


ACCOMPANYING 


THE  MIXTURE  OF  TWO  LIQUIDS 

SEPARATED  BY  A  MEMBRANE. 


THE  constituents  of  the  food,  which  have  assumed  a  The  food  be- 

,          ,  comes  soiu- 

soluble  form  m  the  alimentary  canal,  are  thereby  en-  bie,andintha 
dowed  with  the  property  of  yielding  to  the  influence  of  body  is  sent 
every  cause,  which,  in  acting  on  them,  tends  to  change  lo 
their  place  or  the  position  which  they  occupy.     They 
are  conveyed  into  the  bloodvessels,  and  thence  are  dis- 
tributed to  all  parts  of  the  body. 

The  movement  and  distribution  of  these  fluids,  and 
of  all  the  substances  dissolved  in  them,  exclusive  of  the 
mechanical  cause  of  the  contraction  of  the  heart,  by 
which  the  circulation  of  the  blood  is  effected,  depend, 
—  1.  on  the  permeability  of  the  walls  of  all  vessels  to  General 
these  fluids  ;  2.  on  the  pressure  of  the  atmosphere  ;  their  motion, 
and  3.  on  the  chemical  attraction  which  the  various 
fluids  of  the  body  exert  on  each  other.  The  motion  of 
all  fluids  in  the  body  is  effected  by  means  of  water ; 
and  all  parts  of  the  animal  system  contain,  in  the  nor- 
mal state,  a  certain  amount  of  water. 

Animal  membranes,  tendons,  muscular  fibres,  carti-  Presence  of 

«    ,  water  in  all 

laginous  ligaments,  the  yellow  ligaments  of  the  verte-  membranes. 


130          RELATION  OF  THE  ANIMAL 

bral  column,  the  cornea,  transparent  and  opaque,  &c., 
all  contain,  in  the  fresh  state,  more  than  half  their 
weight  of  water,  which  they  lose,  more  or  less  com- 
pletely, in  dry  air. 

On  the  presence  of  this  water  depend  several  of  their 
physical  properties.  The  fresh,  opaque,  milk-white 
cartilages  of  the  ear  become,  when  dried,  translucent, 
and  acquire  a  reddish-yellow  color.  Tendons,  when 
fresh,  are  in  a  high  degree  flexible  and  elastic,  and  pos- 
sess a  silky  lustre,  which  they  lose  when  dried.  By 
the  same  loss  of  water  they  become,  further,  hard, 
horny,  and  translucent,  and  when  bent,  split  into  whit- 
ish bundles  of  fibres.  The  sclerotic  coat  is  milk-white 
when  fresh,  and  becomes  transparent  by  desiccation. 

When  these  substances,  after  having  lost,  by  drying, 
a  part  of  the  properties  which  they  possess  in  the  fresh 
state,  are  again  placed  in  contact  with  pure  water,  they 
take  up,  in  24  hours,  the  whole  original  amount  of 
water,  and  recover  perfectly  those  properties  which 
they  had  lost.  The  opaque  cornea,  or  sclerotic  coat, 
which  had  become  transparent  by  desiccation,  again  be- 
comes milk-white,  while  the  transparent  cornea,  which 
had  been  rendered  opaque  by  drying,  now  becomes 
again  transparent.  The  tendons,  which,  when  dried, 
had  become  horny,  hard,  and  translucent,  now  again 
become  flexible  and  elastic,  and  recover  their  silky  lus- 
tre. The  fibrine  and  the  cartilages  of  the  ear,  which 
desiccation  had  rendered  horny  and  transparent,  again 
become  milk-white  and  elastic. 

The  tissues  The  power  which  the  solids  of  the  animal  body  pos- 
fluids.  °  r  sess  of  taking  up  water  into  their  substance,  and  of 
being  penetrable  to  water,  extends  to  all  fluids  allied 
to  water,  that  is,  miscible  with  it.  In  the  dried  state, 
the  animal  solids  take  up  fluids  of  the  most  diverse  na- 
tures, such  as  fatty  and  volatile  oils,  ether,  bisulphuret 


TISSUES    TO    WATER.  131 

of  carbon,  &c.  This  permeability  to  fluids  is  possessed 
by  animal  tissues  in  common  with  all  porous  bodies; 
and  no  doubt  can  be  entertained  that  this  property  is 
determined  by  the  same  cause  which  produces  the  as- 
cent of  fluids  in  narrow  tubes,  or  in  the  pores  of  a 
sponge,  —  phenomena  which  we  are  accustomed  to  in- 
clude under  the  name  of  capillary  action. 

One  condition,  essential  to  the  permeability  of  porous  The  moisten- 

,      ,.        P        a    -i     /         i     •  PT-  \-XL-     ing  of  porous 

bodies  for  fluids  (or  their  power  01  absorption),  is  their  bodies 
capability  of  being  moistened,  or  the  attraction  which 
the  particles  of  the  fluid  and  the  walls  of  the  pores  or 
tubes  have  towards  each  otter.  A  second  condition  is 
the  attraction  which  one  particle  of  the  fluid  has  to  an- 
other. We  have  no  means  of  estimating  the  absolute 
size  of  the  particles  or  molecules  of  a  fluid,  such  as 
water,  but  they  are  certainly  infinitely  smaller  than  the 
measurable  diameter  of  a  tube  or  of  the  pores  of  a 
porous  body.  It  is  obvious,  therefore,  that  in  the  inte- 
rior of  a  capillary  tube  or  pore,  filled  with  a  fluid,  only 
a  certain  number  of  the  fluid  molecules  are  in  contact 
with  the  walls  of  the  tube,  and  attracted  by  them  ;  while 
in  the  middle  of  the  tube,  and  thence  towards  its  pa- 
rietes,  fluid  molecules  must  exist  which  only  retain 
their  place  in  virtue  of  the  attraction  which  the  mole- 
cules attracted  by  the  parietes  exert  on  those  not  so  at- 
tracted, that  is,  by  the  cohesive  attraction  of  the  fluid. 

Liquids  flow  out  of  capillary  tubes,  which  are  filled 
with  them,  only  when  some  other  force  or  cause  acts, 
because  capillary  attraction  cannot  produce  motion  be- 
yond the  limits  of  the  solid  body  which  determines  the 
capillary  action. 

The  penetration  of  a  fluid  into  the  pores  of  a  porous  depends  on 

.      ,      .       .  .   .         capillary  at- 

body  is  the  result  of  capillary  attraction ;  its  expulsion  traction. 
can  be  effected  by  a  mechanical  pressure,  and  may  be 
accelerated  by  increasing  this  pressure,  and  by  all  such 


AWIMAL   TISSUES    ARE   POROUS. 

diminish  the  mutual  attraction  of  tj  fluid 
or  the  attraction  of  the  walls  of  the  }  es  for 
these  molecules.  The  condition  most  favorabL  o  the 
JWMge  of  a  fluid  through  the  pores  of  a  por  3  sub- 
stance under  pressure  is  when  one  fluid  molec  *  can 
be  displaced  so  as  to  glide  away  over  another. 

The  slightest  pressure  suffices  to  expel  the  (  ^lace- 
able  particles  of  water  from  a  sponge  ;  a  high<  oress- 
ure  is  required  to  express  the  same  fluid  from  mlous 
paper ;  and  a  pressure  much  higher  still  is  necc  ary  in 
order  to  cause  water  to  flow  out  of  moist  woe  We 
may  form  some  idea  of  the  force  with  whicl  -orous 
organic  substances,  such  as  dry  wood,  absorb  id  re- 
tain water,  if  we  remember,  that,  by  inserting  \v  ges  of 
dry  wood  in  proper  cuts,  and  subsequently  me  ening 
them,  rocks  may  be  split  and  fractured. 

When  we  compare  with  the  properties  just  amer- 
ated,  which  belong  to  all  porous  bodies,  those  -oper- 
ties  which  are  observed  in  animal  substances  u  er  the 
same  circumstances,  it  appears  plainly  that  th  3  ani- 
mal substances  have  pores  in  certain  direct  s,  al- 
though these  openings  are  so  minute  that  they  ;.e  not, 
in  the  case  of  most  tissues,  perceptible  even  h  the 
aid  of  the  hest  microscopes. 

It  has  been  mentioned  that  tendons,  ligamen   carti- 
in,  in  the  fresh  state,  a  certain  mount 
of  water,  which,  apwrfmg  to  all  experiments  r..de  on 
is  inTanabie ;  and  that  several  of  the  prop- 
of  |  nev- 

wrapped  in  bulous 
pressure,  a  >ertain 
i  an  flexi- 
vel- 


OF    LIQUIDS    THROUGH    MEMBRANES.      133 


under  pi  ure,  is  only  found  in  porous  substano 
is  obvioi  that  by  pressure,  that, is,  by  diminution  of 
the  size  the  pores,  only  that  portion  of  water  can 
be  prese  out  which  is  not  retained  by  chemical  at- 
traction, t  is  in  the  highest  degree  worthy  of  notice, 
that  thi.*  ater,  not  chemically  combined,  seems  to 
have  the  rreatest  share  in  the  properties  which 
animal  >stances  possess  in  the  fresh  state,  for  the 
pressed  ndons  and  yellow  ligaments  become  trans- 
parent ;  o  former  lose  their  flexibility,  the  latter  their 
elasticit^  and  if  laid  in  water,  they  recover  these  prop- 
erties pe  'Ctly.  In  the  pores  of  a  porous  substance,  the 
fluid  me  ules  are  retained  by  two  kinds  of  attraction, 
namely.  7  the  affinity  which  is  exerted  between  the 
walls  ot  ie  pores  and  the  molecules  of  the  fluid,  and 
by  the  lesion  which  acts  between  the  molecules  of 
the  fluk  self.  It  would  appear  as  if  the  molecules  of 
thus  brought  into  different  states,  and  this 
seems  to  be  the  cause  of  the  differences 
observed  in  the  properties  of  these  animal 
substances  when  they  contain  different  pro- 
portions of  water. 

If  the  wide  opening  of  the  tube,  Fig.  1, 
be  tied  over  with  a  portion  of  bladder,  and 
water  poured  into  the  wide  part  of  the  tube 
so  far  as  the  mark  a,  we  shall  find  that, 
when  mercury  is  poured  into  the  upright 
narrow  part  of  the  tube  to  a  certain  height, 
the  whole  external  surface  of  the  bladder 
becomes  covered  with  minute  drops,  which, 
if  the  column  of  mercury  be  made  a  few 
lines  higher,  unite  so  as  to  form  large 
drops.  These  continue  to  flow  out  unin- 
terruptedly, if  mercury  be  added  so  as  to 
/  keep  the  column  at  the  same  height,  till 
12 


not  chemical- 
ly combined 
OM  the  great- 
est share  in 
the  proper- 
ties of  the 


water  w 

Fig.  1 


Pressure  re- 
quired to 
force  water 
and  other 

pass  through 


134  PASSAGE    OF    LIQUIDS 

at  last  the  wide  part  of  the  tube  is  emptied  of  water 
and  filled  with  mercury. 

Solution  of  salt,  fat  oil,  alcohol,  &c.,  behave  ex- 
actly as  water  does ;  under  a  certain  pressure  these 
fluids  pass  through  an  animal  membrane,  just  as  water 
does  through  a  paper  fitter. 

The  pressure  required  to  cause  these  liquids  to  flow 
through  the  pores  of  animal  textures  depends  on  the 
thickness  of  the  membrane,  as  well  as  on  the  chemical 
nature  of  the  different  liquids. 

The  pressure       Through  ox-bladder,  y^h  °f  a  ^me   (yiu1^  °f  an 

different"       inch)  thick,  water  flows  under  a  pressure  of  12  inches 

of  mercury ;  a  saturated  solution  of  sea  salt  requires 

from  18  to  20  inches ;  and  oil  (marrow  oil)  only  flows 

out  under  a  pressure  of  34  inches  of  mercury. 

When  the  membrane  used  is  the  peritoneum  of  the 
ox,  ^th  of  a  line  (^yth  °f  an  inch)  in  thickness,  wa- 
ter is  forced  through  it  by  8  to  10  inches,  brine  by  12 
to  16  inches,  oil  by  22  to  24  inches,  and  alcohol  by  36 
to  40  inches  of  mercury. 

The  same  membrane  from  the  calf,  y^th  of  a  line 
(y^g-2-d  of  an  inch)  in  thickness,  allows  water  to  pass 
through  under  the  pressure  of  a  column  of  water  4 
inches  high ;  brine  passes  under  a  pressure  of  8  to  10 
inches  of  brine,  and  oil  under  a  pressure  of  3  inches 
of  mercury. 

In  making  experiments  of  this  nature,  we  observe, 
that,  after  they  have  continued  for  some  time,  the  press- 
ure required  to  force  the  liquid  through  the  membrane 
does  not  continue  equal.  If,  during  the  first  6  hours, 
a  pressure  of  12  inches  of  mercury  were  necessary, 
we  often  find  that,  after  24  or  36  hours,  8  or  even  6 
inches  will  suffice  to  produce  the  same  effect,  obvious- 
ly because,  by  long-continued  contact  with  water,  the 
membrane  undergoes  an  alteration,  in  consequence  pf 
which  the  pores  are  widened. 


THROUGH    MEMBRANES.  135 

From  these  experiments  it  appears  that  the  power 
of  a  liquid  to  filter  through  an  animal  membrane  bears 
no  relation  to  the  mobility  of  its  particles  ;  for  under 
a  pressure  which  causes  water,  brine,  or  oil  to  pass 
through,  the  far  more  mobile  alcohol  does  not  pass. 

The    capacity   of  the    animal  membrane  for  being  Theabsorb- 

i  n  i  •  •  i i     enl  power  of 

moistened  by,  and  its  power  of  absorbing,  the  liquid,  the  mem- 
brane has  a 
have  a  certain  share  in  producing  the  result  of  its  filtra-  share  in  the 

effect. 

tion  through  the  membrane. 

The  following  table  will  show  this  fact :  — 

100  parts,  by  weight,  of  dry  ox-bladder,  take  up,  in 

24  hours,  — 

of  pure  water        '.  .    268  volumes.      Absorption 

of  different 
"   saturated  solution  of  sea  salt  (brine)     .  liquids. 

"   alcohol  of  84  per  cent 38        " 

"   oil  of  marrow         .....  17        u 

100  parts,  by  weight,  of  ox-bladder,  take  up,  in  48 
hours,  — 

of  pure  water           310  parts  by  weight. 

"   a  mixture  of  £  water  and  f  brine  .    219  " 

"            «            h         "          h  brine  .    235  " 

"            "            |         "         I     "  .    288  " 

«            "            £     alcohol     £  water  .      60  " 

"            "            \         "          |     "  181  " 

<c           a           %         u         |     a  290  « 

100  parts  of  dry  pig's  bladder  take  up,  in  24  hours, — 

of  pure  water 356  volumes. 

"   brine 159        " 

"  oil  of  marrow 14        «' 

From  these  experiments  it  appears  that  the  absorp- 
tive power  of  animal  membranes  for  different  liquids  is 
very  different.  Of  all  liquids,  pure  water  is  taken  up 
in  the  largest  quantity ;  and  the  absorptive  power  for 
solution  of  salt  diminishes  in  a  certain  ratio  as  the  pro- 
portion of  salt  increases.  A  similar  relation  holds  be- 
tween the  membranes  and  alcohol ;  for  a  mixture  of 


136  ACTION    OF    SALT,    OIL,    AND    ALCOHOL 

alcohol  and  water  is  taken  up  more  abundantly  the  less 
alcohol  it  contains.* 

cohdandoii  Animal  membranes  do  not  acquire,  by  absorbing  al- 
membranes  coho1  or  oil>  mose  properties  which  they  exhibit  when 
saturated  with  water.  A  dried  bladder  continues  hard 
and  brittle  in  alcohol  and  oil ;  its  flexibility  is  in  no  de- 
gree increased  by  absorbing  these  liquids.  When  ten- 
dons, ligaments  (Chevreul),  the  yellow  ligaments  of 
the  spine  or  bladder,  saturated  with  oil,  are  placed  in 
water,  the  oil  is  completely  expelled,  and  they  take  up 
as  much  water  as  if  they  had  not  previously  been  in 
contact  with  oil. 

inCmoLrcoen-      II  has  been   mentioned,  that   100  parts   of   animal 
'miou>  membrane  (dry  ox-bladder)  absorb,  in  24  hours,  268, 

in  48  hours,  310  volumes  of  water,  and  only  133  of 
saturated  solution  of  salt.  It  follows,  of  course,  that 
when  the  bladder,  saturated  with  water  by  48  hours' 
contact,  and  well  dried  in  bibulous  paper,  without  press- 
ure, to  remove  superfluous  water,  is  strewed  with  salt, 
there  is  formed,  at  all  points  where  salt  comes  in  con- 
tact with  the  water,  filling  the  open  pores,  a  saturated 
solution  of  salt,  the  salt  contained  in  which  diffuses 
itself  equally  in  the  water  of  the  bladder.  Of  the  310 

*  In  regard  to  this  property,  membranes  differ  in  no  respect 
from  other  animal  textures,  as  was  long  ago  proved  by  Chevreul. 
This  distinguished  philosopher  found  that  the  following  substan- 
ces absorbed,  in  24  hours,  of  water,  brine,  and  oil, — 

Cubic 


100 
100 
100 
100 
100 

100 


Ce 
cartilage  of  the  ear     . 

ntimetres   C.  C.         C.  C. 
Water.       Brine.        Oil. 
231            125 
178           114           8.6 
148             30           7.2 
461           370           9.1 
319                           3.2 
301  of  water  and  148  of 
alcohol  of  69  per  cent. 
(Liebig.) 
184  parts  by  weight,  or 
154  by  volume,  ot  brine. 

yellow  ligaments  of  spine 

cartilaginous  ligaments 
dry  fibrine  absorbed 

ON    MEMBRANES    SATURATED   WITH    WATER.        137 

volumes  of  water  which  become  thus  saturated  with 
salt,  only  133  volumes  are  retained  in  the  bladder ;  and 
in  consequence  of  this  diminution  of  the  absorbent 
power  of  the  bladder  for  the  brine,  177  volumes  of 
liquid  are  expelled,  and  run  off  in  drops  from  the  sur- 
face of  the  bladder. 

Membranes,  fibrine,  or  a  mass  of  flesh,  behave  exact- 
ly in  a  similar  manner,  when  in  contact  with  alcohol. 
If  placed  in  alcohol  in  the  fresh  state,  that  is,  when  they 
are  thoroughly  charged  with  water,  there  are  formed, 
at  all  points  where  water  and  alcohol  meet,  mixtures  of 
the  two,  and  as  the  animal  texture  absorbs  much  less 
of  an  alcoholic  mixture  than  of  pure  water,  more  water 
is  of  course  expelled  than  alcohol  taken  up. 

9.17  grammes  of  bladder,  fresh,  that  is,  saturated  Amount  of 
with  water  (in  which  are  contained  6.95  grammes  of  peaiied  from 
water,  and  2.22  of  dry  substance),  when  placed  in  40  akohoi.by 
cubic  centimetres  of  alcohol,  weigh,  at  the  end  of  24 
hours,  4.73  grammes,  and  have,  consequently,  lost  4.44 
grammes.  In  the  4.73  grammes  which  remain  are 
2.22  grammes  of  dry  bladder,  and,  of  course,  2.51 
grammes  of  liquid.  If  we  assume  that  this  liquid  has 
the  same  composition  as  the  surrounding  mixture  (which 
is  found  to  contain  84  parts  of  alcohol  to  16  of  water), 
it  will  consist  of  2.11  grammes  of  alcohol  and  0.40  of 
water;  and,  consequently,  of  the  6.95  grammes  of 
water  originally  present,  6.45  grammes  have  been  ex- 
pelled, and  replaced  by  2. 11  grammes  of  alcohol.  For 
1  volume  of  alcohol,  therefore,  retained  by  the  bladder, 
rather  more  than  3  volumes  of  water  have  been  ex- 
pelled from  it. 

Since,  in  this  case,  so  much  more  water  is  expelled  Moisl  mem. 
than  is  taken  up  of  alcohol,  the  first  result  is  a  shrink-  JjJ?J£ 
ing  of  the  animal  substance.* 

*  Fibrine  and  other  animal  matters  exhibit  results  quite  simi- 
12* 


138        CAUSE  OF  THE  SHRIVELLING  OF 

Pried  salt  If  the  bladder  could  take  up  or  absorb  equal  volumes 

cohoi.  of  brine  and  water,  or  of  alcohol  and  water,  then,  when 

the  fresh  bladder  was  strewed  with  salt,  or  laid  in  alco- 
hol, the  volume  of  the  absorbed  liquid  would  be  unal- 
tered, and  an  equal  volume  of  saline  solution,  or  of  di- 
luted "alcohol,  would  be  retained  by  the  animal  tissue. 
But  since  the  absorbent  power  of  the  tissue  for  water  is 
diminished  by  the  addition  of  salt  or  of  alcohol,  it  fol- 
lows plainly,  that  a  certain  quantity  of  water  must  be 
expelled  as  soon  as  its  character  is  changed  by  the  ad- 
dition of  one  of  these  substances. 

The  cause  of  The  relation  of  bladder,  fibrine,  and  other  animal 
less  affinity  substances,  when  saturated  with  water,  to  alcohol  and 
for  alcohol10  brine,  proves  that  the  shrinking  (diminution  of  volume) 
fc  *  of  these  tissues  does  not  depend  on  a  simple  abstraction 
of  water  in  virtue  of  the  affinity  of  alcohol  and  of  salt 
for  that  liquid  ;  for  it  is  quite  certain  that  the  attraction 
of  alcohol  to  water,  and  that  of  water  to  alcohol,  are 
respectively  equal.  The  attraction  of  the  water  within 
the  tissue  for  the  alcohol  without  is  just  as  strong  as 
the  power  of  the  alcohol  without  to  combine  with  the 
water  within.  Less  alcohol  is  taken  up,  and  more  wa- 
ter given  out,  because  the  animal  tissue  has  less  attrac- 
tion for  the  mixture  of  alcohol  and  water  than  for  pure 
water  alone.  The  alcohol  without  becomes  diluted,  the 
water  within  becomes  mixed  with  a  certain  proportion 
of  alcohol,  and  this  exchange  is  only  arrested  when  the 

lar  to  those  obtained  with  bladder.  26.02  grammes  of  fibrine 
saturated  with  water  (containing  6.48  grammes  of  dry  fibrine  and 
19.54  of  water)  were  reduced,  in  45  grammes  of  absolute  alcohol, 
to  16.12  grammes,  losing,  therefore,  9.90  grammes.  Admitting 
the  absorbed  liquid  to  have  the  composition  of  the  unabsorbed 
residue  (70  per  cent,  of  alcohol),  it  appears,  that  for  1  volume  of 
alcohol  absorbed  by  fibrine,  rather  more  than  2£  volumes  of  wa- 
ter are  separated. 


MEMBRANES    WHEN    STREWED    WITH    SALT.        139 

attraction  of  the  water  for  the  animal  tissue,  and  its  at- 
traction for  alcohol,  come  to  counterpoise  each  other. 

If  we  regard  a  piece  of  skin  or  bladder  or  fibrine  as 
formed  of  a  system  of  capillary  tubes,  the  pores  or  mi- 
nute tubes  are,  in -the  fresh  state,  filled  with  a  watery 
liquid,  which  is  prevented  from  flowing  out  by  capillary 
attraction. 

But  the  liquid  contained  in  these  capillary  tubes  flows 
out  of  them  as  soon  as  its  composition  is  altered  by  the 
addition  of  salt,  alcohol,  or  other  bodies. 

If  we  lay  together,  one  over  the  other,  two  portions  Expert- 
of  bladder,  saturated  with  solution  of  salt  of  sp.  g.  m 
1.204,  and  over  the  upper  one  another  piece  of  bladder 
of  equal  size,  saturated  with  water,  and  if  we  allow 
them  to  remain  thus,  without  pressure,  we  find,  after 
some  minutes,  when  the  two  pieces  saturated  with  so- 
lution of  salt  are  separated,  that  drops  of  saline  solution 
appear  between  them,  of  which  no  trace  could  pre- 
viously be  perceived.  If  the  piece  of  bladder  saturated 
with  water  contained  5  volumes  of  water,  and  the  next 
piece  3  volumes  of  saline  solution,  there  must  be  pro- 
duced, by  the  mixture  of  both,  8  volumes  of  diluted 
saline  solution,  of  which  each  piece  of  bladder  must 
contain  one  half,  or  4  volumes,  if  the  absorbent  power 
of  the  portion  saturated  with  the  original  saline  solution 
were  increased  by  the  addition  of  water  in  the  same 
ratio  as  the  absorbent  power  of  the  portion  saturated 
with  water  was  diminished  by  the  addition  of  salt.  The 
saline  liquid  would  have  given  up  1^-  volumes  of  saline 
solution  to  the  other,  and  would  have  received  from  it 
21  volumes  of  water.  In  this  case,  the  mixture  in  the 
two  upper  pieces  of  bladder  would  occupy  the  same 
space  which  its  constituents,  water  and  saline  solution, 
occupied  in  each  singly.  But  the  efflux  of  the  liquid 
towards  the  third  or  lowest  piece  of  bladder,  saturated 


140 


ANIMAL    TISSUES   ARE 


Animal  tis- 


with  saline  solution,  proves  that  the  two  upper  pieces 
retain  a  smaller  volume  of  the  mixture  newly  formed 
in  their  pores  than  the  one  piece  absorbed  of  water 
alone,  and  the  other  of  saline  solution  alone.  The 
power  of  retaining  water  is  diminished  by  the  addition 
of  salt  to  the  bladder  saturated  with  water  ;  liquid  is 
expelled  ;  but  by  the  addition  of  this  water  to  the  blad- 
der moistened  with  saline  solution,  the  absorbent  power 
of  this  piece  of  bladder  is  increased,  not  in  the  same 
ratio  according  to  which  the  proportion  of  salt  is  di- 
minished, but  in  a  less  ratio. 

The  experiments  above  described  show  that  the  at- 
traction of  the  porous  substances  for  the  water  which 
they  have  absorbed  does  not  prevent  the  mixture  of  this 
water  with  other  liquids. 

The  permeability  of  animal  tissues  to  liquids  of  every 
kind,  and  the  miscibility  of  the  absorbed  liquids  with 
others  which  are  brought  in  contact  with  the  tissues, 
may  be  demonstrated  by  the  simplest  experiments. 

If  we  moisten  one  side  of  a  thin  membrane  with  fer- 
rocyanide  of  potassium,  and  the  opposite  side  with 
chloride  of  iron  in  solution,  we  perceive  in  the  sub- 
stance of  the  membrane  a  spot  of  Prussian  blue  imme- 
diately deposited.  (Job.  Miiller.) 
which  act  on  All  fluids  which,  when  brought  together,  suffer  a 

each  other  in      i  .,  .,  .  i  -i  • 

the  substance  change  in  their  nature  or  in  their  properties,  exhibit, 
when  only  separated  by  an  animal  membrane,  exactly 
analogous  results;  they  mix  in  the  pores  of  the  mem- 
brane, and  the  decomposition  commences  in  its  sub- 
stance. 

If  we  tie  up  one  end  of  a  cylindrical  glass  tube  with 
bladder,  and  fill  it  to  the  height  of  3  or  4  inches  with 
water  or  strong  brine,  neither  the  water  nor  the  brine 
flows  out  through  the  pores  of  Jhe  bladder  under  this 
slight  pressure. 


every  k?nd, 


PERMEABLE    TO    ALL    LIQUIDS.  141 

But  if  we  leave  the  tube  containing  brine  exposed  to  Deposit  of 
evaporation  in  the  air,  the  side  of  the  bladder  exposed  outside  of 

,  i  T       .  ,  ,        „        ,          ,  .    ,     bladder  from 

to  the  air  is  soon  covered  with  crystals  of  salt,  which  brine  on  the 
gradually  increase,  so  as  to  form  a  thick  crust.  It  is  m 
obvious  that  the  pores  of  the  bladder  become  filled  with 
brine ;  that,  on  the  side  exposed  to  the  air,  the  water 
evaporates;  its  place  is  supplied  by  fresh  brine,  and 
the  dissolved  salt  is  deposited,  at  the  external  minute 
openings  of  the  pores,  in  the  form  of  crystals.  If  the 
tube  be  filled  originally  with  dilute  saline  solution,  the 
crust  of  salt  is  not  formed  on  the  outer  surface  of  the 
bladder  until  the  solution  in  the  tube  has  reached,  by 
evaporation,  the  maximum  of  saturation.  Before  this 
takes  place,  we  can  perceive  in  the  tube,  if  we  set  the 
liquid  in  motion,  two  strata,  a  heavier  and  a  lighter,  the 
latter  swimming  on  the  former.  When  these  strata  can 
no  longer  be  observed,  the  liquid  is  in  every  part  satu- 
rated with  salt,  and  now,  by  further  evaporation,  crys- 
tals are  deposited  on  the  outer  surface  of  the  bladder. 
This  last  circumstance  proves  that  the  amount  of  salt 
in  the  liquid  is  uniformly  distributed  from  below  up- 
wards, from  the  specifically  heavier  to  the  specifically 
lighter  part. 

If  we  immerse  the  tube  closed  with  bladder,  and  The  solutions 
filled  with  saline  solution,  in  pure  water,  the  latter  ac-  through  wa- 
quires  the  property  of  precipitating  nitrate  of  silver, 
even  when  the  contact  has  lasted  only  the  fraction  of  a 
second.     The  brine  filling  the  open  pores  of  the  mem- 
brane mixes  with  the  pure  water,  and  the  latter  acquires 
a  certain  quantity  of  salt. 

In  like  manner,  the  pure  water  acquires  a  saline  im- 
pregnation, when  it  is  placed  in  the  tube  instead  of 
brine,  and  the  outer  surface  of  the  bladder  is  placed 
in  contact  with  solution  of  salt. 

When  the  tube,  closed  with  bladder,  and  filled  with 


142  ENDOSMOSIS    AND    EXOSMOSIS. 

brine,  is  left  for  a  long  time  with  the  closed  end  im- 
mersed in  pure  water,  the  amount  of  salt  in  the  latter 
increases,  while  that  of  the  brine  diminishes,  till  at  last 
the  two  liquids,  separated  by  the  bladder,  contain  the 
same  relative  proportions  of  salt  and  water. 

The  same  is        If  the  liquid  in  the  tube  contain,  dissolved,  other  sub- 
true  of  milk 
and  serum,     stances,  which  give  to  it  properties  different  from  those 

of  pure  water,  and  if  these  solutions  be  miscible  with 
water,  the  mixture  of  them  with  the  water  takes  place 
exactly  as  in  the  case  of  brine.  This  is  true  of  saline 
solutions  of  every  kind ;  of  bile,  milk,  urine,  serum  of 
blood,  syrup,  solution  of  gum,  &c.,  on  the  one  side,  and 
pure  water,  on  the  other.  The  concentrated  liquid 
loses,  the  water  or  diluted  liquid  gains,  in  regard  to 
saline  impregnation. 

If  we  fill  the  tube  with  water,  and  place  it  in  a  vessel 
with  alcohol,  the  water  becomes  charged  with  alcohol, 
while  the  alcohol  becomes  diluted  with  water. 
Change  of          There  is  observed,  in  these  circumstances,  that  is, 
dissimilar       when  two  dissimilar  liquids,  separated  by  a  membrane, 
ti?roughPbiad-  mix  together,  a  phenomenon  of  a  peculiar  kind ;  name- 
ly, in  most  cases,  a  change  of  volume  in  both  liquids, 
while  the  mixture  goes  on.     The  one  liquid  increases 
in  bulk,  and  rises ;  the  other  diminishes  in  the  same 
degree,  and  consequently  sinks  below  its  original  level. 
Endosmosis         This  phenomenon  of  mixture  through  a  membrane, 
Ii9.  °"  accompanied  with  change  of  volume,  has  been  distin- 

guished by  Dutrochet,  under  the  name  of  Endosmosis 
and  Exosmosis ;  endosmose  is  the  name  given  when  the 
volume  increases,  —  exosmose,  when  it  diminishes.  Very 
generally,  however,  we  attach  to  these  terms  the  idea 
of  the  unknown  cause  or  group  of  causes  which,  in  the 
given  case,  produce  the  change  of  volume  ;  in  the 
same  sense  as  that  in  which  the  term  capillary  action 
includes  the  causes  which  determine  the  ascent  of  liq- 
uids in  narrow  tubes. 


INFLUENCE    OF    DENSITY. 


143 


In  all  cases,  the  increase  in  volume  of  the  one  liquid 
is  exactly  equal  to  the  decrease  in  volume  of  the  other, 
after  making  allowance  for  the  contraction  which  the 
liquids  undergo  by  simple  mixture  (as  in  the  case  -of 
alcohol  and  water,  oil  of  vitriol  and  water,  &c.),  as  well 
as  by  evaporation.  The  unequal  concentration  or  the 
unequal  density  of  the  two  liquids  has  a  decided  influ- 
ence on  the  rapidity  with  which  the  change  of  volume 
takes  place  ;  but  this  cannot  be  viewed  as  the  cause  of 
that  phenomenon.  In  most  cases,  the  denser  liquid  in- 
creases in  volume ;  in  others,  the  reverse  occurs. 

When,  for  example,  the  tube  contains  brine,  and  the 
outer  vessel  pure  water,  the  brine,  that  is,  the  denser 
liquid,  increases  in  volume  ;  but  when  the  tube  contains 
water,  and  the  outer  vessel  alcohol,  the  water,  that  is, 
the  denser  liquid,  diminishes  in  volume. 

With  regard  to  the  mixture  of  the  liquids,  the  blad- 
der takes  a  distinct  share  in  the  process,  inasmuch  as 
it  has  pores,  through  which  the  two  liquids  are  brought 
in  contact. 

With  reference  to  the  porosity  of  the  bladder,  the 
rapidity  of  the  mixture  of  the  two  liquids  is  dtrectly 
proportional  to  the  number  of  particles  which,  in  a 
given  time,  come  into  contact ;  it  de- 
pends also  on  the  surface  (the  size  of 
the  membrane),  and  on  the  specific 
gravity  of  the  liquids. 

The  influence  of  the  extent  of  sur- 
face on  the  time  required  for  mixture 
requires  no  particular  elucidation ;  that 
of  the  unequal  specific  gravity  is  ren- 
dered evident  by  the  following  exper- 
iments. 

If  the  bent  tube  a  I  (Fig.  2),  one 
end  of  which  is  tied  over  with  blad- 


Change  of 
volume  does 
not  depend 
alone  on  the 
different  den- 
sities of  the 
liquids. 


Fig.  2. 


Influence  of 
the  unequal 
density  of  th« 
liquids 


when  the 
lighter  liquid 
is  above  the 
membrane. 


144  CONDITION    OF   THE    MIXTURE, 

der,  and  the  other  open,  be  filled  with  brine  colored 
blue,*  and  if  pure  water  be  placed  in  the  tube  c,  there 
is  soon  perceived  under  the  bladder  a  colorless  or 
nearly  colorless  stratum  of  liquid,  which  continues  for 
hours  to  float  in  the  same  place.  If  the  bent  tube  a  b 
be  filled  with  colorless  brine,  while  c  is  filled  with 
pure  water  colored  blue,  there  is  found,  after  a  time, 
above  the  bladder,  a  colorless  or  nearly  colorless  stra- 
tum of  liquid. 

It  appears  from  this,  that  an  exchange  of  both  liquids 
goes  on  through  the  substance  of  the  bladder ;  in  the 
first  experiment  colorless  water  passes  from  the  tube 
c  to  the  colored  brine  in  the  tube  a  b ;  in  the  second, 
colorless  brine  passes  from  the  tube  a  b  to  the  colored 
water  in  the  tube  c. 

It  is  obvious,  that  the  brine  in  the  tube  a  5,  which 
is  in  contact  with  the  bladder,  becomes  diluted  by  the 
addition  of  water  from  the  tube  c ;  but  this  diluted 
brine  is  specifically  lighter  than  the  original  brine 
which  is  below  it,  and  remains  therefore  floating  at 
its  surface. 

On»the  other  hand,  the  water  in  the  tube  c,  when 
mixed  with  brine  from  the  tube  a  5,  becomes  heavier 
than  the  pure  water,  and  rests  therefore  on  the  upper 
surface  of  the  bladder,  or  that  which  is  turned  towards 
the  water. 

Hence  it  follows,  that  from  the  moment  when  these 
two  strata  have  been  formed  above  and  below  the 


*  For  this  purpose  it  is  best  to  take  a  solution  of  indigo  in  sul- 
phuric acid,  diluted,  and,  after  adding  subacetate  of  lead  as  long 
as  sulphoindigotate  and  sulphate  of  lead  are  precipitated,  to  sepa- 
rate the  precipitate  by  filtration  and  dry  up  the  filtered  liquid 
in  the  water-bath.  A  mere  trace  of  the  blue  residue  suffices  to 
give  blueness  to  large  masses  of  liquid. 


THROUGH    MEMBRANES,    OF    TWO    LIQUIDS. 


145 


bladder,   neither   concentrated   brine   nor   pure   water 
comes  any  longer  in  contact  with  the  bladder. 

From  the  bladder  downwards  in  the  tube  a  I  are 
strata  of  liquid,  containing  successively  more  salt;  from 
the  bladder  upwards  in  the  tube  c  are  strata  containing 
successively  more  water. 

In  the  beginning  of  this  experiment  we  observe  that 
the  volume  of  the  water  and  of  the  brine  changes  in 
both  tubes  ;  the  liquid  in  the  limb  b  rises  from  1  to 
2  lines;  but  as  soon  as  the  strata  above  mentioned 
have  been  distinctly  formed  above  and  below  the  blad- 
der, hardly  any  further  rise  is  perceptible,  although 
the  mixture  of  the  liquid  proceeds,  and  the  water  in 
c  becomes  constantly  more  charged  with  salt,  while 
the  brine  in  a  b  loses  salt. 

If  we  reverse  the  positions  of  the  two  liquids  in  the 
apparatus,  Fig.  2,  or,  what  is  simpler,  if  we  close  with 
bladder  a  tube  1  centimetre  (TVhs  of  an  inch)  wide, 
fill  it  with  brine,  and  immerse  the  end  closed  with 
the  bladder  in  a  wider  vessel  filled  with  pure  wa- 
ter, giving  to  the  tube  an  inclination  of  about  45°, 
we  may  observe  (most  distinctly 
when  both  liquids  contain  some 
fine  particles  of  indigo  suspended) 
in  both  liquids  a  continual  motion. 
We  see  in  the  tube  (Fig.  3)  a  cur- 
rent of  liquid  rising  from  the  blad- 
der in  the  direction  of  the  arrow, 
and  flowing  down  again  on  the  op- 
posite side.  A  similar  circulation 
is  observable  in  the  vessel  of  water. 
If  the  tube  0,  with  brine,  is  about  2  centimetres 
(fths  of  an  inch)  wide,  and  if  we  support  it  vertically 
in  the  vessel  b  of  water,  the  motion  proceds  from  the 
middle,  and  in  both  the  tube  and  the  vessel  we  per- 
13 


Fig.  3. 


146 


PHENOMENA    OF    THE    MIXTURE 


ceive  currents   in   opposite  directions. 
(Fig.  4.) 

These  currents  hardly  require  ex- 
planation. To  the  brine  in  the  tube 
a,  pure  water  passes  through  the  blad- 
der ;  there  is  formed  above  the  blad- 
der a  mixture  containing  less  salt,  and 
therefore  specifically  lighter  than  the 
brine ;  this  mixture  rises,  and  the  (Jens- 
er  brine  descends  to  occupy  its  place. 

On  the  other  hand,  the  pure  water  receives  through 
the  bladder  salt,  and  becomes  thereby  specifically 
heavier ;  while  it  sinks  to  the  bottom  of  the  vessel,  its 
place  is  supplied  by  water  containing  less  or  no  salt, 
and  therefore  specifically  lighter,  which  again  comes 
in  contact  with  the  bladder.  As  long  as  the  motions 
just  described  are  perceptible,  we  observe  a  constant 
increase  in  the  volume  of  the  brine  in  the  tube  a  (Fig. 
4),  or  a  diminution  in  the  volume  of  the  pure  water 
in  the  vessel  b.  When  the  motions  cease,  the  rise  of 
liquid  in  the  tube  is  arrested,  and  when  this  takes 
place,  the  two  liquids  are  found  to  possess  almost  ex- 
actly the  same  specific  gravity. 

When  the  two  strata  of  liquid  on  either  side  of  the 
bladder  are  little  different  in  composition  (as  soon 
comes  to  pass  in  the  experiment  (Fig.  2)  where  the 
saline  contents  of  the  liquid  which  fills  the  pores  of 
the  bladder  can  hardly  vary  from  that  of  the  next 
stratum),  the  mixture  of  the  liquids  takes  place,  but 
without  further  change  of  volume.  But  when  an  ex- 
change of  the  mixtures  on  the  opposite  sides  of  the 
bladder  can  occur  in  consequence  of  their  different 
specific  gravity,  and  when  a  continued  difference  be- 
tween the  strata  on  opposite  sides  of  the  bladder  is 
thus  determined,  then,  so  long  as  (in  the  case  of  brine 


OF    TWO    LIQUIDS    THROUGH   A    MEMBRANE. 


147 


and  water,  for  example)  one  side  of  the  bladder  is  in 
contact  with  a  concentrated,  the  other  with  a  more 
diluted  solution,  the  change  of  volume  in  the  two  liq- 
uids continues. 

As  appears  from  these  experiments,  the  change  of 
volume  depends  on  a  difference  in  the  character -of  the 
two  liquids  which  are  connected  through  the  bladder ; 
and  the  time  during  which  change  of  volume  occurs 
is  in  direct  proportion  to  the  time  during  which  this 
difference  in  character  subsists.  The  greater  the  differ- 
ence in  character  and  composition  between  the  liquids, 
and  the  more  rapidly  this  difference  is  renewed  by 
the  exchange  between  the  strata  in  contact  with  the 
opposite  sides  of  the  bladder,  the  more  rapidly  does  the 
one  liquid  increase,  and  the  other  diminish,  in  volume. 

The  following  apparatus  is  very  convenient  for  meas-  The  change 

,          ,  .  ,  111-  f*  m  volume 

unng  the  change  in  volume  caused  by  the  mixture  of  made  by  a 

i.       .  i  .11  membrane 

two  liquids  separated  by  a  membrane. 


Fig.  5. 


The  tubes  a  and  b  (Fig.  5)  are  of 
equal  width,  and  are  best  taken  from 
the  same  tube  ;  a  is  closed  with  bladder, 
and  filled  up  to  a  certain  point  with  the 
liquid  whose  increase  in  volume  is  to  be 
determined.  It  is  then  fitted  by  means 
of  a  good  cork  into  the  wider  tube  c, 
which  contains  distilled  water,  care  be- 
ing taken  to  exclude  all  air-bubbles. 
At  d  lies  a  small  lead  drop,,  which  acts 
as  a  valve  in  shutting  the  opening  of 
jjj  the  capillary  tube  connecting  c  with  I. 
Pure  water  is  now  poured  into  5,  and 
in  order  to  keep  in  equilibrium  the  lead 
drop  at  d,  rather  more  water  is  added 
than  exactly  suffices  to  bring  the  liquids 
to  the  same  level  in  both  tubes. 


148 


PHENOMENA    OF    THE    MIXTURE 


The  liquid  in  a  increases  in  volume,  and  the  height 
to  which  it  rises  may  be  read  off  by  means  of  any 
division  into  equal  parts  by  measure  ;  the  level  of  the 
liquid  in  b  sinks  in  an  equal  ratio.  If  we  keep  the 
liquid  in  Z>,  by  the  addition  of  fresh  water,  at  the  origi- 
nal level,  and  if  we  ascertain  the  weight  of  the  added 
water,  by  pouring  it  out  of  a  dropping  bottle,  and  de- 
termining the  loss  of  weight  in  the  dropping  bottle, 
we  learn  at  the  same  time  the  weight  and  the  volume 
of  the  water  which  has  risen  from  c  into  a.  This  ap- 
paratus admits,  of  course,  of  a  number  of  variations 
and  improvements.  I  have  employed  it  to  determine 
the  relation  between  brine  and  water,  under  the  cir- 
cumstances just  described.  It  appeared,  among  other 
things,  that  when  the  tube  a  is  filled  with  saturated 
solution  of  sea  salt,  the  volume  of  the  liquid  increased 
by  nearly  one  half;  that  is,  200  volumes  of  such  a 
solution  increased  to  300.  These  deter- 
minations are,  however,  not  the  object  of 
the  present  investigation,  and  therefore  I 
pass  them  over  entirely. 

The  following  arrangement  (Fig.  6)  will 
probably  be  found  preferable  to  the  one 
just  described,  in  many  cases.  Its  con- 
struction depends  on  the  observation,  that, 
for  the  phenomenon  itself,  and  for  the  re- 
sult of  the  experiment,  it  is  entirely  a  mat- 
ter of  indifference  whether  the  tube  be 
closed  with  a  single,  double,  or  treble  lay- 
er of  bladder.*  For  experiments  on  very 
thin  membranes  which  are  permeable  to 
liquids  under  a  very  low  pressure,  the 
apparatus  (Fig.  5)  is  obviously  better 

*  In  these  experiments  membranes  of  all  kinds  may  be  used. 
With  the  thinner  membranes,  such  as  the  bladder  of  the  calf 


Fig.  6. 


OF    TWO    LIQUIDS    THROUGH   A    MEMBRANE.  149 

adapted.  For  the  explanation  of  the  phenomenon,  we 
have  to  distinguish,  — 

1.  The  mixture  of  different  liquids, 

2.  The  change  in  their  volume. 

As  to  the  mixture  of  two  liquids  of  dissimilar  nature  Cause  of  the 

motion  of 

and  characters,  this  always  depends  on  a  chemical  at-  dissimilar 

.         liquids. 

traction.  In  a  mixture  of  alcohol  and  water,  or  of  brine 
and  water,  there  is  in  every  part  the  same  proportion  of 
particles  of  alcohol  and  water,  or  of  salt  and  water.  If, 
in  the  former,  the  lighter  particles  of  alcohol  lying  at 
the  bottom  of  the  vessel  were  not  retained  in  the  place 
and  arrangement  which  they  occupy  by  the  surrounding 
particles  of  water,  they  would  undoubtedly  rise  towards 
the  surface.  In  like  manner,  the  particles  of  salt  in 
the  brine  are  sustained  and  prevented  from  sinking 
by  the  lighter  particles  of  water  which  surround  them. 

Without  an  attraction,  which  all  the  particles  of  al- 
cohol or  of  salt  must  have  towards  all  the  particles 
of  water,  or  all  the  particles  of  water  must  have  for 
all  those  of  salt  and  alcohol,  a  uniform  mixture  cannot 
even  be  conceived.  If  but  one  particle  of  alcohol 
were  less  powerfully  attracted  than  the  surrounding 
particles,  it  would  rise  to  the  surface  ;  and,  in  like  man- 
ner, the  particles  of  salt  would,  in  consequence  of  their 
greater  specific  gravity,  gradually  occupy  the  bottom 
of  the  vessel,  were  it  not  that  a  cause  prevents  them 
from  rising  or  falling ;  and  this  cause  can  be  nothing 
but  an  attractive  force,  which  retains  them  in  the  place 
where  they  happen  to  be. 

The  cause  which  effects  a  change  in  the  place  or  Chemical  at- 

,  ./.,,.  •   i  traction  is 

m  the   properties  of  the  ultimate   particles  or  atoms  the  cause  of 

the  motion  of 

and  the  pig,  the  experiments  are  more  rapidly  completed  than 
with  the  thicker,  such  as  the  gall-bladder  and  urinary  bladder 
of  the  ox.  The  peritoneum  of  the  ox  and  calf  is  preferable  to 
all  others.  The  tube  c  is  tied  with  bladder  under  water. 

13* 


150  CHEMICAL    AFFINITY 

of  dissimilar  substances,  when  these  particles  are  in  ab- 
solute contact,  or  at  infinitely  small  distances  from  each 
other,  as  well  as  the  cause  which  manifests  itself  as  a 
resistance  to  such  changes  of  place  or  properties,  we 
call  chemical  attraction ;  and  in  this  sense  the  mix- 
ture of  two  dissimilar  liquids,  the  simple  moistening  of 
a  solid  body,  the  penetration  and  swelling  of  it  by  a 
liquid,  are  effects  in  which  chemical  affinity  or  attraction 
has  a  decided  share ;  and  although  we  are  accustomed 
to  limit  the  notion  of  affinity  to  such  cases  as  exhibit  a 
change  perceptible  to  our  senses,  in  the  properties  of 
the  substances  employed,  as,  for  example,  when  sul- 
phuric acid  and  lime,  or  sulphur  and  mercury,  combine 
together,  this  limitation  arises  from  the  imperfect  appre- 
hension of  the  essence  of  a  natural  force. 

Affinity  is          Everywhere,  when  two  dissimilar   bodies   come   in 

act[veWbeere     contact,  chemical  affinity  is  manifested.     It  is  a  univer- 

IrTcontact!68  sal  property  of  matter,  and  by  no  means  belongs  to  a 

peculiar  class  of  atoms,  or  to  a  peculiar  arrangement 

of  these.     But   chemical   combination   is   not,   in    all 

cases,  the  result  of  contact. 

Combination  is  only  one  of  the  effects  of  affinity, 
and  occurs  when  the  attraction  is  stronger  than  all  the 
obstacles  which  are  opposed  to  its  manifestation. 
When  the  forces  or  causes  which  oppose  chemical 
combination  —  heat,  cohesive  attraction,  electric  attrac- 
tion, or  whatever  they  may  be  called  —  preponderate, 
then  chemical  combination  does  not  take  place  ;  and 
effects  of  another  kind  are  manifested. 

Melted  silver  in  a  crucible,  surrounded  with  red-hot 
coals,  in  a  place,  therefore,  where  we  should  hardly 
anticipate  the  presence  of  free  oxygen,  absorbs  as 
much  as  ten  or  twelve  times  its  volume  of  that  gas. 
Metallic  platinum  exhibits  the  same  property  in  a  far 
higher  degree  ;  for  from  the  atmospheric  air,  a  gas- 


IS  UNIVERSALLY  DIFFUSED.          151 

eons  mixture  in  which  oxygen  forms  only  the  fifth  part, 
that  metal  (in  the  form  of  a  black  powder)  condenses 
on  its  surface,  at  the  ordinary  temperature,  an  enor- 
mous quantity  of  oxygen  gas  (without  any  nitrogen), 
and  acquires  thereby  properties  which  it  does  not 
otherwise  possess.*  And  when  oxide  of  chromium, 
fragments  of  porcelain,  or  asbestos,  at  high  tempera- 
tures, effect  the  combination  of  two  gases,  oxygen  and 
hydrogen,  or  oxygen  and  sulphurous  acid,  which  gases 
do  not  combine  at  the  same  temperature,  unless  when 
in  contact  with  these  solid  bodies,  it  is  to  the  chemical 
attraction  or  affinity  of  these  solid  bodies  that  we  must 
ascribe  this  effect. 

The  solution  of  a  salt  in  water  is  an  effect  of  affin- 
ity, and  yet  no  one  property,  either  of  the  salt  or  of 
the  solvent,  is  thereby  altered,  except  only  the  cohe- 
sion of  the  saline  particles. 

Sea  salt,  the  crystals  of  which  are  usually  anhydrous,  Crystaiiiza- 

.  _0  n  lion  of  sea 

takes  up,  at  very  low  temperatures,  38  per  cent,  of  salt, 
water  of  crystallization ;  not  because  any  new  cause 
acts  which  increases  its  affinity  for  the  particles  of 
water  (for  cold  is  no  cause,  but  the  absence  of  a  cause), 
but  because  the  higher  temperature  acted  as  an  obsta- 
cle, opposing  their  chemical  combination.  The  force 
of  affinity  is  all  the  time  present  and  undiminished. 

When  we  add  alcohol  to  the  solution  of  a  salt  in  Precipitation 

of  salt  from 

water,  we  observe  that  now  the  salt  separates  from  the  its  solution 
liquid  in  the  form  of  crystals,  doubtless  only  because, 
by  the  addition  of  another  chemical  force,  the  amount 
of  attraction  between  the  particles  of  the  salt  and  those 
of  the  water  has  been  altered. 

The  aqueous  particles,  which   were  combined  with 

*  According  to  Doebereiner,  platinum  black  condenses  252 
times  its  volume  of  oxygen.  Its  effect  in  oxidizing  alcohol, 
pyroxilic  spirit,  &c.,  is  familiar  to  every  chemist.  —  W.  G. 


152  ACTION    OF    LIQUIDS   AND  SOLIDS 

the  saline  particles,  manifest  an  attraction  for  the  par- 
ticles of  alcohol ;  and  as  the  latter  have  no  affinity,  or 
only  a  very  feeble  affinity,  for  those  of  the  salt,  the 
attraction  of  the  saline  particles  for  each  other  is 
strengthened.  This  attraction  was  present  in  equal 
force  before  the  addition  of  the  alcohol,  but  the  resist- 
ance which  opposed  their  union  (the  chemical  attrac- 
tion for  them  of  the  aqueous  particles)  was  more  pow- 
erful. The  alcohol  was  not  the  cause  of  the  separa- 
tion. The  cause  of  the  separation  of  the  salt  from 
the  liquid,  its  crystallization,  is  at  all  times  the  force  of 
cohesion ;  and  by  the  alcohol  the  cause  which  opposed 
its  manifestation  was  removed. 

Precipitation  The  affinity  of  potash  for  sulphuric  acid  is  known, 
of  potash  by  and  sulphate  of  potash  readily  dissolves  in  water.  If 
we  add  to  a  saturated  solution  of  that  salt  an  equal  vol- 
ume of  aqua  potassse  of  sp.  g.  1.4,  there  is  immediate- 
ly formed  a  crystalline  precipitate  of  sulphate  of  pot- 
ash, and  the  sulphuric  acid  is  separated  in  this  form 
from  the  water. 

In  these  cases  the  chemical  effect  (the  separation) 
depends  on  the  presence  of  a  certain  quantity  of  the 
liquid  which  is  added  (such  as  aqua  potassse,  alcohol, 
&c.) ;  but  in  many  other  cases  there  is  required  only  a 
slight  alteration  in  the  quality  of  the  solvent  to  effect 
separations  of  this  kind. 

Precipitation       When  hydrochloric  acid  is  added  to  a  solution  of  fer- 
rocyanfcfacid  rocyanide  of  potassium,  hydroferrocyanic   acid   is  set 
by  ether.        ^^  an(j  remams  dissolved  in  the  liquid.     If  now  the 
vapor  of  boiling  ether  be  passed  through  the  mixture, 
there  occurs,  after  a  few  moments,  a  complete  separa- 
tion.    The  whole  of  the  hydroferrocyanic  acid  is  de- 
posited from  the  liquid  in  the  form  of  white  or  bluish- 
white   crystalline   scales,   which   generally   appear  in 
such  quantity  as  to  render  the  whole  mass  semi-solid. 


ON  DISSOLVED  MATTERS.  153 

In  proportion  as  the  vapor  of  ether  is  dissolved  by 
the  water,  the  latter  fluid  loses  entirely  its  solvent  power 
(its  affinity)  for  the  hydroferrocyanic  acid.  The  coagu- 
lation of  albumen  by  ether  depends  on  a  similar  cause. 

The  capacity  of  solids  to  become  moistened  by 
liquids,  and,  in  short,  all  phenomena  connected  with 
chemical  affinity,  are  affected,  altered,  increased,  or 
destroyed  by  causes  quite  analogous. 

After  heavy  rains,  the  water  of  many  rivers  becomes 
turbid  and  opaque  from  the  presence  of  a  fine  clay. 
These  suspended  particles  of  clay  are  so  fine  as  to  pass 
through  the  finest  filters ;  and  their  adhesion  to  the 
water  is  so  great,  that  such  water  does  not  clear  after 
standing  for  weeks.  The  water  of  the  Yellow  River, 
in  China,  possesses,  during  the  greater  part  of  the  year, 
this  character ;  and  from  the  French  missionaries  we 
know  that  alum  is  universally  employed  in  Pekin  to 
clear  it.  In  fact,  if  a  crystal  of  alum  be  held  in  such 
a  water  only  for  a  few  seconds,  we  observe  the  sedi- 
ment separating  in  large,  thick,  flocculent  masses,  the 
water  becomes  transparent,  and  hardly  a  trace  of  dis- 
solved alum  is  to  be  detected  by  the  most  delicate  re- 
agents. Chemistry  is  acquainted  with  a  number  of 
similar  means  for  causing  the  separation  from  liquids  of 
suspended  precipitates. 

In  these  cases  we  see,  that,  by  an  alteration  of  the 
quality  of  the  water,  produced  by  what  we  call  mere 
mixture  with  a  foreign  body,  its  power  of  combining 
with  others  is  destroyed  or  weakened. 

It  is  well  known  that  the  force  with  which,  in  a  solu-  Action  of 

..  _  .  .     ,  «.         ,.       solids  on  dis- 

tion,  the  particles  of  the  liquid  and  those  of  the  dis-  solved  mat- 
solved  body  attract  each  other  is  very  unequal  in  differ- 
ent  cases ;  and   in    this  point   of  view  the    action  of 
many  solid  bodies  on  saline  solutions  is  very  remarka- 
ble,   inasmuch  as    it  is  thereby  demonstrated  that  the 


154      ACTION    OF    SOLIDS    ON    DISSOLVED    MATTERS  ; 

molecular  force,  which  determines  the  phenomena  of 
cohesion,  and  the  moistening  of  solid  bodies  by  .liquids, 
appears  to  be  identical  with  chemical  affinity,  since 
chemical  compounds  can  be  decomposed  by  means  of 
it.  Professor  Graham  has  shown  that  common  char- 
coal, deprived  by  acids  of  all  soluble  ingredients,  com- 
pletely removes  the  metallic  salts  or  oxides  from  solu- 
tions of  salts  of  lead,  tartar  emetic,  ammoniated  oxide 
of  copper,  chloride  of  silver  in  ammonia,  and  oxide  of 
zinc  in  ammonia ;  while  other  solutions,  such  as  that  of 
sea  salt,  suffer  no  such  change.  A  bleaching  solution 
of  hypochlorite  of  soda  loses  entirely  its  bleaching  prop- 
erties by  agitation  with  charcoal ;  and  iodine  can  be 
removed  by  the  same  means  from  its  solution  in  iodide 
of  potassium.  Every  one  is  familiar  with  the  action 
of  finely  divided  platinum,  with  that  of  silver,  on  the 
deutoxide  of  hydrogen  ;  as  well  as  with  that  of  char- 
coal on  dissolved  organic  matters,  coloring  matters, 
&c.  ;  and  freshly  precipitated  sulphuret  of  lead,  sulphu- 
ret  of  copper,  and  hydrate  of  alumina  resemble  the  lat- 
ter in  their  action.  Many  organic  substances,  such  as 
woody  fibre  and  others,  act  on  dissolved  matters,  such 
as  salts  of  alumina  or  of  oxide  of  tin,  just  as  charcoal 
does;  and  we  know  that  the  application  of  mordants  in 
dyeing,  and  dyeing  itself,  depend  on  this  very  property. 
The  adhesion  of  the  solid  coloring  matter  to  the  cloth 
which  is  died  with  it  is  the  result  of  a  chemical  affinity 
so  feeble,  that  we  hardly  venture  to  give  the  molecular 
force  that  name  in  this  case.  From  a  piece  of  woollen 
cloth  dyed  with  indigo,  the  indigo  is  completely  separat- 
ed, by  mere  beating,  continued  for  some  time,  with  a 
wooden  hammer,  so  that  the  wool  is  at  last  left  white. 

The  surface  of  the  solid  body  exerts,  as  these  facts 
prove,  a  very  unequal  attraction  on  the  molecules 
which  come  in  contact  with  it. 


OF   TWO    DIFFERENT    LIQUIDS.  155 

Researches  on  capillary  attraction  have  shown,  that, 
with  one  and  the  same  liquid,  water,  for  example,  the 
substance  of  the  solid  body  has  no  influence  on  the 
height  to  which  the  liquid  rises  on  it.  On  slices  of  box- 
wood, clay-slate,  or  glass,  the  rise  of  the  liquid  above 
the  surface  of  the  water  is  the  same  exactly  as  in  the 
case  of  a  plate  of  brass.  (Hagen.)  In  the  case  of 
other  liquids,  the  particles  of  which  are  entirely  homo- 
geneous, the  same  law  may  be  assumed  in  theory ;  -but 
with  such  liquids  as  contain  foreign  bodies  in  solution, 
a  change  in  the  capillary  attraction  must  be  produced 
by  the  presence  of  these  bodies,  because  by  them  the 
cohesion  of  the  liquid  is  altered  ;  and  perhaps  still  more, 
because  the  liquid  ceases  to  be  homogeneous  when 
the  attracting  wall  has  a  stronger  affinity  for  the  particles 
of  the  dissolved  body  than  for  those  of  the  solvent. 

From  what  has  been  stated,  it  appears  that  the  mix- 
ture of  two  liquids  is  the  result  of  a  chemical  attrac- 
tion; for  how  otherwise  could  chemical  compounds, 
such  as  the  solution  of  a  salt  in  water,  be  decomposed, 
or  a  chemical  attraction  be  overcome,  by  its  means  ? 

Two  liquids  of  different  chemical  properties,  which  Laws  of  the 

mixture  of 

are  miscible   together,    and    which,   therefore,  have  a  two  dissimi- 
lar liquids. 
chemical  attraction  for  each  other,  mix  readily  at  all 

points  where  they  come  in  contact.  By  motion,  shak- 
ing, &c.,  the  number  of  points  of  contact  within  a  giv- 
en time  is  increased,  and  the  formation  of  a  Uniform 
mixture  is  thus  accelerated. 

If  these  liquids  be  of  equal,  or  still  better,  of  un- 
equal, specific  gravity,  they  may  be,  with  the  aid  of 
some  precaution,  stratified  one  above  the  other.  This 
is,  in  point  of  time,  the  most  unfavorable  case  for  the 
mixture,  since  proportionally  small  surfaces  come  in 
contact.  But  wherever  they  do  come  in  contact,  it  is, 
after  a  very  short  time,  impossible  to  detect  any  limit 
between  them. 


156 


LAWS    OF    THE    MIXTURE 


In  a  cylindrical  vessel,  containing  solution  of  salt, 
the  saline  particles  at  the  surface  are  attracted  and  sus- 
tained by  aqueous  particles,  which  exist  at  the  sides  of 
the  saline  particles,  and  from  the  surface  downwards. 
From  the  surface  upwards,  the  attracting  aqueous  parti- 
cles are  absent. 

Now  it  is  evident,  that,  when  the  surface  is  brought  in 
contact  with  pure  water,  a  new  attraction  is  added  to 
those  previously  existing,  which  acts  in  an  opposite  di- 
rection, namely,  the  attraction  of  the  aqueous  particles 
floating  on  the  surface  for  the  saline  particles,  and  vice 
versa  (the  attraction  of  the  saline  particles  to  the 
aqueous  particles  in  contact  with  them). 

At  the  place  where  pure  water  and  brine  are  in  con- 
tact, there  is  thus  formed  a  uniform  mixture  of  the  two, 
which  upwards  is  in  contact  with  pure  water,  down- 
wards with  brine. 

Among  these  three  strata,  of  which  the  upper  con- 
tains no  salt,  the  lower  less  water,  a  new  division  takes 
place  ;  the  more  strongly  saline  stratum  loses  salt,  the 
pure  water  becomes  saline,  and  in  this  way  salt  and 
water  are  at  last  uniformly  distributed  throughout  the 
liquid. 

Experiments  If  we  fill  the  limb  of  the  tube  (Fig.  7),  Fig  7i 
formationof  as  far  as  a,  with  brine  colored  blue,  and 
uvoTiqUukis.f  *ne  other  limb  with  water,  we  find,  in  the 
course  of  a  few  days,  the  water  colored 
blue,  and  the  proportion  of  salt  in  both 
limbs  equal.  It  has  been  mentioned  at 
p.  141,  that  in  a  tube  closed  with  bladder, 
filled  with  diluted  solution  of  salt,  and 
exposed  to  evaporation,  the  salt  is  not  de- 
posited in  crystals  on  the  outer  surface  of 
the  bladder  till  the  whole  liquid  in  the 
tube  has  reached,  in  consequence  of  evap- 


OF    DIFFERENT    LIQUIDS.  157 

oration,  the  maximum  of  saturation.  The  water  evap- 
orates from  the  exterior  of  the  bladder,  but  no  salt  is 
deposited  as  long  as  a  liquid  exists  within  which  salt 
can  still  dissolve ;  and  in  this  way  the  heavier  saline 
particles  are  distributed  towards  the  interior,  and  up- 
wards through  the  whole  liquid,  or,  what  amounts  to  the 
same,  the  lighter  aqueous  particles,  which  can  still  dis- 
solve salt,  are  distributed  downwards  towards  the  exter- 
nal surface  of  the  bladder. 

This  distribution  of  salt  through  water  takes  place  in  The  distru.u- 

3  .  lion  of  salt 

the  same  manner  as  the  conversion  of  bar  iron  into  through  wa- 

*  T>  •  ter  resembles 

sreel.     Rods  of  malleable  iron,  as  is  well  known,  are  theconver- 

....       sion  of  iron 

kept  ignited  between  strata  of  charcoal,  whereby  the  to  steel  by 
surface  of  the  iron  in  contact  with  the  charcoal  takes 
up  carbon,  and  becomes  a  carburet  of  iron.  The  stra- 
tum of  iron  lying  next  under  this  surface,  which  has 
the  same  attraction  for  carbon,  acquires  carbon  from 
the  superficial  stratum  immediately  in  contact  with  it, 
and  in  its  turn  gives  carbon  to  the  stratum  below  itself. 
This  process,  if  continued  long  enough,  has  no  limit  till 
all  the  strata  of  particles  have  acquired  an  equal  pro- 
portion of  carbon,  that  is,  till  they  are  all  saturated  with 
it.  A  piece  of  red-hot  malleable  iron,  if  kept  a  few 
moments  in  contact  with  pig  iron  (a  carburet  of  iron), 
is  found  to  be  already  converted  into  steel  at  the  points 
of  contact.  The  mixture  of  liquids  depends  on  the 
same  principle ;  and  we  may  suppose  that  their  distri- 
bution is  mutual,  because  their  particles  may  move  in 
all  directions,  and  that  consequently  saline  particles 
move  towards  aqueous  particles,  as  well  as  aqueous 
towards  saline  particles,  in  virtue  of  their  mutual  at- 
traction. 

From  a  solution  of  sulphate  of  copper  in  ammonia, 
placed  in  a  tall  glass  cylinder,  there  is  gradually  sepa- 
rated, if  we  pour  a  stratum  of  alcohol  on  the  surface, 
14 


158  LAWS    OF    THE    MIXTURE 

and  if  we  prevent  the  formation  of  a  coherent  crust 
which  impedes  the  contact  of  the  liquids,  the  whole  of 
the  ammoniated  sulphate  of  copper,  while  the  deep  blue 
solution  becomes  colorless,  because  by  the  distribution 
of  the  alcohol  through  the  solution  a  mixture  is  formed, 
in  which  the  salt  is  insoluble. 

Mixture  is         The  rapidity  of  mixture  of  two  liquids  depends  on 

chemical        the  degree  of  their  chemical  affinity ;  and  the  unequal 

mobility  of  the  particles  of  one  or  the  other  liquid  has 

a  favorable  or  unfavorable  influence  on  the  result. 

by  unequal         When  the  one  liquid  is  heavier  than  the  other,  and  of 

mobility,  and  ,          •,        .      .  -, 

by  unequal     tough,  viscid  consistence,  a  much  longer  time  elapses 

theiiquids.     before  the  ingredients  of  the  tougher  or  heavier  liquid 

reach  the  surface  from  the  bottom  of  the  vessel ;  and 

in  this  case  the  greater  density  and  the  less  mobility  of 

the  particles  are  obstacles  to  the  mixture. 

On  the  other  hand,  if  the  heavier  or  more  viscid 
liquid  be  placed  above  the  lighter,  the  mixture  takes 
place  rapidly ;  at  the  points  where  both  liquids  are  in 
contact  is  produced  a  mixture,  which,  being  heavier,  de- 
scends, whereby  the  heavier  liquid  above  is  continually 
brought  in  contact  with  new  surfaces  of  liquid. 
Effect  of  po-  The  very  same  phenomenon  is  observed  in  solution. 

sition  on  the      A     _ 

solution  of  a  A  fragment  of  sugar,  when  covered  with  water  at  the 
bottom  of  a  narrow  cylinder,  dissolves  very  slowly, 
while,  if  suspended  just  below  the  surface,  it  rapidly 
disappears.  In  the  former  case  there  is  produced  round 
the  sugar  a  thick,  syrupy,  viscid  solution,  which  pro- 
tects the  undissolved  part  of  the  sugar  for  a  long  time 
from  contact  with  the  water;  in  the  latter,  there  is 
formed  at  the  surface  a  solution,  which  descends  in 
striae,  and  gradually  disappears,  while,  by  the  change  of 
place  thus  induced,  new  portions  of  water  are  constant- 
ly brought  in  contact  with  the  undissolved  sugar,  and 
are  thus  enabled  to  exert  their  solvent  powers. 


OF    TWO    DIFFERENT    LIQUIDS.  159 

If  skin  and  membranes  consist  of  a  cohering  system 
of  very  narrow  tubes,  it  is  obvious  tbat  when  two  dis- 
similar but  miscible  liquids  are  separated  by  such  a 
tissue,  the  pores  of  the  tissue  will  fill  with  each  of  the 
two  liquids.  In  all  situations  where  the  liquids  come  in 
contact  in  the  substance  of  the  membrane,  a  mixture 
takes  place,  and  this  mixture  is  extended  equally  tow- 
ards both  sides. 

If  there  be  brine  on  one  side  of  the  bladder,  and 
water  on  the  other,  there  must  be  formed,  in  the  middle, 
or  at  some  point  of  the  bladder,  a  diluted  brine,  which 
on  the  side  in  contact  with  the  water  yields  salt  to  that 
water,  while  on  the  opposite  side  the  strong  brine  mixes 
with  the  diluted  brine  in  the  bladder. 

The  substance  of  the  bladder  has  no  influence  on  this 
mixture,  because  it  can  produce  no  change  of  place  on 
the  part  of  the  saline  or  aqueous  particles,  for  this  is 
the  result  of  the  chemical  affinity  acting  between  the 
particles  of  salt  and  those  of  water. 

Now,  since  the  rapidity  of  the  mixture  of  two  liquids  Rapidity  of . 
stands  in  a  direct  proportion  to  the  amount  of  their  sur- 
faces coming  into  contact  within  a  given  time,  and 
since  the  liquids,  separated  by  a  bladder,  can  only  come 
in  contact  through  its  pores,  while  the  number  of  points 
of  contact  is  diminished  by  the  presence  of  the  non- 
porous  parts  of  the  bladder,  it  follows,  that,  exclusive  of 
all  other  effects,  the  time  required  for  mixture  must  be 
lengthened  by  the  interposition  of  a  bladder.  In  the 
absence  of  the  bladder,  the  mixture  would  take  place 
exactly  as  when  it  is  present,  except  in  regard  to 
time. 

When  the  heavier  brine  is  under  the  water  above  the 
bladder,  the  two  liquids  mix  more  slowly  than  without 
the  bladder. 

But  since  a  bladder,  inasmuch  as  a  feeble  hydrostat-  incertaincir- 

cwmstauees 


160      CAUSE  OF  THE  CHANGE  OF  VOLUME  IN 

the  interpo-     ical  pressure  is  not  propagated  through  its  pores,  allows 

sition  of  a  .          .  . 

membrane      us  to  place  a  heavier  liquid  above  a  lighter,  and  to  re- 

accelerates  .... 

mixture.  tain  it  in  that  position,  this  circumstance  has  the  effect 
of  promoting  mixture,  the  ultimate  cause  of  which  is, 
not  the"  bladder,  but  the  specific  gravity  of  the  liquid. 
The  bladder  is  a  means  of  enabling  the  specific  gravity 
to  influence  mixture.  The  foregoing  remarks  appear 
to  me  sufficiently  to  elucidate  the  share  taken  by  the 
bladder  in  the  mixture  of  two  dissimilar  liquids  placed 
on  opposite  sides  of  it. 

change  of          With  respect  to  the  change  of  volume  in  the  two 
two  liqukis     liquids  which  become  mixed  through  the  bladders,  we 
through  a      must   consider  that   the    moistening   or  the    absorbent 
power  of  a  solid  body,  as  well  as  the  power  of  a  liquid 
to  moisten  other  bodies,  is  the  result  of  a  chemical  ac- 
tion, 
is  the  result        Liquids  of  different  properties,  or  of  different  chemi- 

of  chemical  ,       ,  . 

affinity  mod-  cal  characters,  are  attracted  with  unequal  degrees  of 
lary  attrac-  force  by  solid  bodies,  and  exert  towards  them  unequal 
degrees  of  attraction,  and  if  we  alter  even  in  a  system 
of  capillary  tubes,  filled  to  a  certain  height  with  a 
liquid,  the  chemical  nature  of  that  liquid,  we  change 
thereby  the  height  at  which  the  liquid  stands.  In  an 
animal  tissue  saturated  with  water,  the  water  is  pre- 
vented from  flowing  out  by  the  mutual  attraction,  and 
by  the  capillary  force,  but  if  the  attraction  of  the  or- 
ganic parietes  for  water  be  diminished  by  the  addition 
of  alcohol  or  of  salt  to  the  water,  a  part  of  it  flows  out. 
To  this  must  be  added,  that  the  water  absorbed  by  an 
animal  texture  when  it  enters  the  capillary  tubes  exerts, 
in  virtue  of  its  attraction  for  the  tubes,  a  certain  press- 
ure, by  which  the  vessels  are  swollen  and  enlarged. 
The  particles  of  liquid  in  these  tubes  uridergo  a  counter- 
pressure  from  the  elastic  parietes,  by  which  pressure, 
when  the  attraction  of  the  liquid  particles  for  the  solids 


LIQUIDS    MIXING   THROUGH    A    MEMBRANE.  161 

is  diminished  by  any  new  cause,  the  amount  of  expelled 
fluid  is  increased. 

The  organic  parietes  of  the  tubes,  saturated  with 
water,  are  affected  by  alcohol  just  as  a  salt  is  when  dis- 
solved in  water.  On  the  addition  of  alcohol,  or  of  an- 
other liquid,  the  water  separates  from  the  salt,  or  from 
the  parietes,  or  the  parietes  separate  from  the  water. 

If  the  animal  tissue  possessed  as  great  an  attraction 
for  the  newly  formed  mixture  as  for  the  water  alone, 
the  volume  of  the  liquid  would  not  change.  The  mix- 
ture would  take  place,  but  no  water  would  flow  out. 

A  bladder,  saturated  with  water,  when  brought  in 
contact  with  alcohol,  shrinks  together,  a  part  of  the 
water  separates  from  the  animal  matter,  but  there  al- 
ways remains  in  the  bladder  a  certain  amount  of  water, 
corresponding  to  its  attraction  for  the  bladder  and  for 
the  alcohol ;  just  as  the  solutions  of  many  salts  which 
have  a  strong  attraction  for  water  (such  as  metaphos- 
phate  and  acid  phosphate  of  soda),  and  are  insoluble  in 
alcohol,  are  separated  by  the  addition  of  alcohol  into 
two  strata  of  liquid,  the  heavier  of  which  is  a  more 
concentrated  solution  of  the  salt  in  water,  containing  a 
little  alcohol,  while  the  other,  the  lighter,  is  an  aque- 
ous liquid  containing  much  alcohol.  The  alcohol  and 
the  salt  divide  between  them  the  water  of  the  solu- 
tion. 

When  we  add,  to  a  mixture  of  equal  parts  of  acetone  Action  of 
and  water,  a  certain  quantity  of  dry  fragments  of  chlo-  calcium  on 
ride  of  calcium,  the   first  fragments  which   are  added  LTtoXnTan°df 
deliquesce  and  dissolve  entirely  in  the  mixture.     But  if  water< 
we  go  on  adding  the  salt,  a  separation  soon  occurs,  two 
strata  of  liquid  are  formed,  of  which  the  upper  contains 
acetone  and  water,  the  other  is  an  aqueous  solution  of 
the  chloride  with  a  little  acetone.     If  we  add  still  more 
of  the  chloride,  water  is  abstracted  from  the  acetone  of 
14* 


162  EFFECT    OF   EVAPORATION    ON 

the  upper  stratum,  and  when  a  proper  quantity  has  been 
added,  the  acetone  retains  no  trace  of  water. 

If  we  suppose,  that  of  the  two  originally  formed 
strata  of  liquid,  one  of  them,  namely,  that  which  sinks 
and  contains  chloride  of  calcium  dissolved,  is  in  con- 
tact with  a  current  of  dry  air,  the  water  of  this  solution 
will  evaporate,  the  solution  will  thus  become  stronger, 
and  in  consequence  of  its  increased  concentration  will 
be  able  to  remove  a  new  portion  of  water  from  the 
mixture  of  acetone  and  water  above  it ;  and  this  will 
continue  till  the  acetone  is  entirely  deprived  of  water. 

If  in  the  place  of  the  chloride  of  calcium  we  put  a 
bladder,  and,  in  place  of  the  acetone  and  water,  diluted 
alcohol,  we  have  the  finest  example  of  the  unequal  at- 
traction which  the  animal  tissue  exerts  on  the  two  ingre- 
dients of  the  mixed  liquid. 
Effect  of  It  is  known,  from  the  experiments  of  Soemmering, 

evaporation 

upon  a  mix-    that  spirits  of  a  certain  strength  inclosed  in  a  bladder, 

ture  of  alco-  .  . 

hoi  and  water  which  is  exposed  to  the  air,  lose  by  evaporation  only 
water,  and  that  at  last  anhydrous,  or  nearly  anhydrous 
(absolute),  alcohol  is  left  in  the  bladder.  When  strong 
spirits  of  wine  are  used,  the  bladder  remains  dry  exter- 
nally ;  when  weaker  spirits  are  employed,  it  becomes 
moist,  and  alcohol  evaporates  with  the  water.  In  virtue 
of  the  unequal  affinity  of  the  bladder  for  alcohol  and 
for  water,  a  complete  separation  is  here  effected.  The 
water  of  the  mixture  is  absorbed,  and  evaporates  from 
the  outside  of  the  bladder ;  the  alcohol  remains  in  the 
bladder.  As  yet,  we  are  acquainted  with  no  substance 
which  can  replace  the  bladder  in  this  operation ;  and 
indeed  the  affinity  of  the  gelatinous  tissues  (membranes, 
&c.)  for  water  must  exceed  that  of  all  other  animal 
tissues,  since  a  rise  of  temperature,  of  a  few  degrees 
only,  suffices  to  enable  water  to  dissolve  that  tissue  per- 
fectly into  a  jelly. 


LIQUIDS    CONFINED    BY    MEMBRANES.  163 

Magnus  assumes  "  that  the  particles  of  every  solu-  views  of 

i  /»  i,     •  ji  Magnus  on 

tion,  for  example,  of  a  salt  in  water,  adhere  more  Endosmosis. 
strongly  to  each  other  than  do  those  of  the  solvent,  for 
example,  of  water ;  consequently,  the  solution  would 
be  less  fluid,  and  pass  with  greater  difficulty  through 
very  narrow  openings,  than  water,  if  we  take  for  granted 
that  the  parietes  of  the  openings  act  alike  towards  both. 
It  would  follow  from  this,  that,  the  more  concentrated  a 
solution,  the  less  easily  would  it  pass  through  the  same 
openings." 

"  Let  us  now  try,"  pursues  Magnus,  u  with  the  aid  of 
these  assumptions  (which,  as  appears  from  the  experi- 
ment, Fig.  1,  are  perfectly  accurate  and  demonstrable 
for  many  saline  solutions,  although  there  are,  according 
to  the  researches  of  Poiseuille,  a  number  of  excep- 
tions*), to  explain  the  phenomena  of  Endosmosis." 

"  Both  the  brine  and  the  water  will  penetrate  into 
the  pores  of  the  bladder,  and  brine  will  pass  from  the 
pores  to  the  water,  as  well  as  water  to  the  brine,  in 
virtue  of  their  mutual  attraction,  till  a  complete  equi- 
librium is  established.  Further,  since  the  force  which 
attracts  the  water  to  the  brine  is  exactly  the  same  as 
that  which  attracts  the  brine  to  the  water,  as  much  wa- 
ter as  brine  would  pass  through  the  bladder,  if  both 
liquids  could  pass  with  equal  facility  through  the  pores. 
Since,  however,  this  is  not  the  case,  unequal  forces 
are  required  to  urge  the  two  liquids  through  the  pores; 
or,  with  equal  forces,  unequal  quantities  of  the  two  pass 
through  in  equal  times.  There  is,  consequently,  added 
more  of  that  which  passes  most  easily,  the  water  to  the 
brine,  than  of  the  latter  to  the  water,  and  the  level  of 
both  liquids  must  change,  if  no  other  force  oppose  this 
change."  f 

*  Ann.  de  Ch.  et  de  Phys.,  3d  Series,  XXI.  pp.  84  et  seq. 
\  Poggendorff's  Annales,  X.  p.  164. 


164  VIEWS    OF    MAGNUS 

According  to  this  theory,  brine  and  water  exist  in  the 
pores  of  the  bladder  in  a  state  of  motion,  and  the 
chemical  affinity  which  the  particles  of  the  brine  have 
for  the  particles  of  the  pure  water,  and,  conversely, 
which  the  particles  of  water  have  for  those  of  salt,  is 
considered  as  the  cause  of  this  motion.  The  unequal 
velocity,  which  makes  more  water  flow  in  a  given  time 
to  the  brine  than  brine  or  salt  to  the  pure  water  is,  ac- 
cording to  %Iagnus,  .determined  by  the  unequal  resist- 
ance which  the  substance  of  the  bladder  opposes  to  the 
passage  of  the  two  liquids. 

Now,  however  narrow  the  tubes  may  be  in  which 
molecules  are  set  in  motion  by  an  external  force,  it 
may  always  be  assumed,  that  that  part  of  the  mole- 
cules which  is  immediately  in  contact  with  the  wall  of 
the  tube  either  is  not  in  motion,  or  possesses  only  a 
small  velocity,  and  the  velocity  of  efflux  must  be  a 
function  of  the  cohesion,  and  at  all  events  not  depend- 
ent on  the  wall  of  the  tube. 

If  now  the  efflux  of  the  water  on  one  side  of  the 
bladder  is  produced  by  the  attraction  of  the  saline  par- 
ticles for  the  water,  and  the  efflux  of  the  brine  on  the 
other  side  is  produced  by  the  attraction  of  the  aqueous 
particles  for  the  saline  particles,  it  is  impossible  to  ex- 
plain how  water  and  brine  can  move  in  the  same  tube 
with  unequal  velocity  in  opposite  directions  ;  the  two 
liquids  being  supposed  to  have  a  mutual  attraction,  that 
is,  to  be  miscible.  This  attraction  must  act  within  the 
tube  just  as  well  as  without ;  and  we  might  therefore 
suppose,  that,  when  the  two  liquids  have  become  mixed, 
the  mixture  could  only  move  in  one  direction  with  a 
medium  velocity. 

Assuming  that  a  mixture  is  formed  in  the  open  orifi- 
ces of  the  pores  or  tubes,  or  in  any  part  of  them,  it  is 
difficult  to  see  why  saline  particles  should  not  pass 


ON    ENDOS3IOSIS    EXAMINED.  165 

from  one  side  to  the  water,  or  aqueous  particles  to  the 
saline  ones  in  the  bladder,  since  the  mutual  attraction 
must  be  regarded  as  equal  on  both  sides.  The  chem- 
ical affinity  of  the  two  liquids  does  not  explain  the 
efflux. 

If  we  suppose,  that  in  certain  pores  only  brine,  in 
others  only,  pure  water,  moves,  the  phenomenon  ought 
not  to  occur  when  all  the  pores  are  filled  with  water  or 
with  brine,  or  when  the  tube  is  tied  with  a  double, 
treble,  or  fourfold  bladder.  But  the  properties  of  blad- 
der are  seen  in  the  finest  as  well  as  thickest  membranes, 
and  one,  two,  or  three  layers  make  no  difference  in 
the  ultimate  result.* 

*  With  respect  to  the  theory,  that,  when  a  saline  solution  is 
mixed  with  pure  water,  if  the  two  liquids  are  separated  by  a 
membrane,  particles  of  salt  alone  pass  through  the  pores  of  the 
bladder  to  the  water,  and  particles  of  water  alone  to  the  brine, 
the  following  experiments  may  throw  some  light  on  the  ques- 
tion. For  the  sake  of  greater  accuracy,  the  results  were  deter- 
mined by  weighing.  The  apparatus  Fig.  3  was  used.  The 
tube  contained  8.67  grammes  of  saturated  brine,  in  which  were 
2.284  grammes  of  salt  and  6.38  of  water.  After  24  hours  it  had 
gained  1.79  grammes  in  weight,  and  it  now  contained  only  0.941 
grammes  of  salt.  It  had,  therefore,  lost  1.343  grammes  of  salt, 
and  gained  3.13  of  water.  According  to  the  above  theory,  1 
atom  of  salt  and  15  atoms  of  water  must  have  moved  past  each 
other;  but  this  is  impossible,  since  1  atom  of  salt  requires  18 
atoms  of  water  for  solution  (10  parts  of  salt  to  27  of  water). 
The  weight  of  the  pure  water  in  the  outer  vessel  was  19.26 
grammes  ;  consequently,  the  weight  of  the  brine  was  to  that  of 
the  pure  water  as  1  :  2.22.  In  another  experiment,  in  which 
the  weight  of  the  brine  in  the  tube  was  to  that  of  the  water  out- 
side, as  1  :  7.98,  the  tube  gained  0.822  grammes  in  weight ;  the 
liquid  in  the  tube  contained  at  first  0.947  grammes  ef  salt ;  and 
24  hours  after,  0.148  grammes:  hence,  1.621  grammes  of  water 
had  entered,  while  0  799  grammes  of  salt  had  passed  out.  For 
1  atom  of  salt,  which  passed  from  the  tube  with  brine  to  the 
vessel  with  water,  there  passed  from  the  latter  to  the  former 
rather  more  than  13  atoms  of  water  (for  58.6  parts,  or  1  atom 
of  salt,  118  parts  of  water). 


166 


THE    MIXTURE    IS    INFLUENCED    BY    THE 


The  nature 
of  the  mem- 
brane has  an 
important  in- 
fluence. 


Experiments 
with  bladder 


and  caout- 
chouc. 


Experiment 
to  prove  the 
attraction  of 
the  bladder 
for  the 
liquid. 


The  kind  of  influence  which  the  nature  of  the  par- 
tition, or  its  attraction  for  the  liquids  in  contact  with  it, 
exerts  on  the  phenomenon,  is  seen  by  comparing  the 
action  of  an  animal  membrane  with  that  of  a  thin  sheet 
of  caoutchouc. 

In  a  tube,  closed  with  bladder,  which  is  filled  with 
alcohol  and  immersed  in  pure  water,  the  volume  of  the 
alcohol  is  increased  ;  more  water  passes  to  the  alcohol 
than  alcohol  to  the  water. 

If,  without  making  any  other  change  in  the  exper- 
iment, the  tube  be  closed  with  a  thin  sheet  of  caout- 
chouc, the  volume  of  the  alcoliol  now  diminishes,  while 
that  of  the  water  increases. 

Here,  all  the  circumstances  of  the  mixture  of  the 
two  liquids  have  remained  the  same,  except  the  nature 
of  the  partition,  which  makes  the  difference  in  the 
result. 

When  we  fill  with  brine  a  tube 
closed  with  bladder  (Fig.  8),  and 
place  it  in  a  vessel  of  water,  so  that 
the  bladder  and  water  only  commu- 
nicate by  a  single  drop,  the  liquid  in 
the  tube  increases  in  bulk,  and  rises 
in  the  tube,  as  if  the  bladder  had 
been  immersed  in  the  water ;  but 
the  drop  becomes  gradually  smaller, 
till,  after  an  hour  or  two,  a  complete 
separation  takes  place,  and  the  drop  tears  itself  away 
from  the  water.* 

If  the  cause  of  the  change  of  volume  in  this  exper- 

*  If  we  pour  into  a  tube  £  of  an  inch  wide,  and  closed  with 
bladder,  as  much  mercury  as  covers  the  surface  of  the  bladder, 
then  fill  it  with  brine,  and  place  it  in  pure  water,  the  volume  of 
the  liquid  in  the  tube  increases  exactly  as  if  the  mercury  were 
not  there. 


ATTRACTION  OF  THE  MEMBRANE  FOR  THE  LIQUIDS.    167 

iment  were  the  unequal  resistance  which  the  bladder  Unequal  at- 

.  .  j   traction  of 

opposes  to  the  passage  01  the  two  liquids  with  equal  membrane 

.  .  .          .  for  different 

attraction  (equal  force)  on  both  sides,  the  phenomenon  liquids, 
just  described  would  be  inexplicable  ;  for  a  resistance 
can  no  doubt  impede,  but  is  not  capable  of  producing, 
motion.  But  we  see  that  the  water  in  this  experiment 
is  raised  to  a  higher  level,  and,  moreover,  the  tearing 
asunder  of  the  drop  can  only  be  the  effect  of  a  pow- 
erful attraction,  residing  in  the  substance  of  the  blad- 
der. 

If  the  moistening  of  solid  bodies  by  liquids  be  the 
effect  of  a  chemical  attraction,  the  force  of  which  is 
different  in  dissimilar  liquids,  it  follows,  that  when  a 
porous  body  is  saturated  with  a  liquid,  and  brought  in 
contact  with  a  second  liquid,  which  has  a  stronger  at- 
traction for  its  substance  than  the  first  has,  then  the  first 
liquid  must  be  displaced  from  the  pores  by  the  second, 
even  in  the  absence  of  hydrostatic  pressure,  and  this 
whether  the  two  liquids  be  miscible  or  not. 

We  may  suppose  that  the  attraction  of  the  second 
liquid,  of  more  powerful  affinity,  which  displaces  the 
other,  is  equal  to  the  pressure  of  the  column  of  mer- 
cury required  to  force  the  latter  through  the  porous 
substance. 

If  we  tie  over  one  end  of  a  cylindrical  tube  with  a 
very  thin  membrane,  saturated  with  concentrated  brine 
by  steeping  for  24  hours,  and  if  we  dry  the  outer  sur- 
face of  the  membrane  carefully  with  bibulous  paper, 
and  now  pour  a  few  drops  of  pure  water  into  the  tube 
so  as  just  to  cover  the  inner  surface  of  the  membrane, 
the  outer  surface  is  seen  in  a  few  moments  to  be  cov- 
ered with  minute  drops  of  brine  ;  that  is,  brine  flows 
out  of  the  pores  of  the  bladder. 

A  thick  ox-bladder,  saturated  with  oil,  exhibits  the 
same  phenomenon  in  contact  with  water.  The  oil  is 


168  UNEQUAL   ATTRACTION    OF    MEMBRANES 

expelled  from  the  pores  of  the  bladder  by  the  water, 
which  occupies  its  place. 

Explanation.  When  the  bladder  is  brought  in  contact  with  pure 
water,  it  takes  up  a  certain  quantity  of  that  liquid. 
If  its  pores  are  previously  filled  with  brine,  and  if  we 
cover  one  side  of  it  with  pure  water,  the  water  mixes 
with  the  brine  in  the  pores  of  the  bladder  ;  and  on  the 
side  next  the  water  there  is  formed  a  diluted  brine, 
which,  being  in  contact  with  a  stratum  of  pure  water, 
mixes  with  it,  and  in  this  way  the  successive  strata  of 
water  receive,  from  the  bladder  outwards,  a  certain 
quantity  of  salt. 

In  the  interior  of  the  bladder,  there  are  formed  in 
like  manner,  towards  the  outer  surface,  mixtures  of 
unequal  saline  strength.  If  we  suppose  the  bladder  to 
consist  of  several  strata,  all  these  strata  receive,  from 
the  surface  in  contact  with  the  water,  a  certain  quanti- 
ty of  water ;  the  outer  stratum,  in  contact  with  the 
air,  receives  least,  and  is  the  most  highly  charged  with 
salt. 

The  cause  of  mixture  is  the  chemical  affinity  of  the 
salt  for  the  newly  added  particles  of  water ;  this  affinity 
is  equal  on  both  sides,  but  the  attraction  of  the  sub- 
stance of  the  bladder  is  stronger  for  the  more  aqueous 
or  less  saline  liquid  than  for  the  more  concentrated. 
In  consequence  of  this  difference  in  the  attraction  of 
the  liquids  for  the  substance  of  the  bladder,  a  part  of 
the  mixture  is  displaced  from  the  bladder ;  the  less 
saline  liquid  takes  the  place  of  the  more  saline  ;  a  part 
of  the  latter  is  expelled,  and  with  it  a  part  of  that 
water  which  has  been  added  to  the  outer  stratum  by 
mixture.  Brine  and  water  flow  out  .in  the  direction  of 
least  resistance.  The  efflux  towards  the  side  on  which 
the  pure  water  was  poured  is  prevented  by  the  stronger 
attraction  of  the  more  watery  liquid  for  the  substance 
of  the  bladder. 


FOR   DIFFERENT    LIQUIDS.  169 

If  we  remove  from  the  outer  surface  of  the  bladder 
the  displaced  saline  liquid  (which  has  been  mixed  with 
some  water),  and  put  stronger  brine  in  its  place,  and  if 
on  the  opposite  side  we  remove  the  very  diluted  solu- 
tion, replacing  it  by  a  still  more  diluted  one,  the  same 
process  is  repeated.  There  arises  a  permanent  differ- 
ence, and  a  state  of  mixture  and  efflux  continues  till 
the  liquids  on  the  opposite  surfaces  of  the  bladder  have 
the  same,  or  very  nearly  the  same,  composition. 

If  we  suppose  that  the  two  liquids  moisten  the  blad- 
der unequally,  it  follows,  that,  in  addition  to  the  chem- 
ical attraction  which  the  dissimilar  particles  of  the 
liquids  have  for  each  other,  a  new  cause,  namely,  the 
stronger  attraction  of  one  of  them  for  the  substance  of 
the  partition,  is  introduced,  which  accelerates  their  mo- 
tion or  passage,  and  must  have  this  effect,  that  one  of 
them  flows  out  in  larger  quantity,  in  the  same  time,, 
than  the  other. 

The  experiments  (Fig.  3)  elucidate  this  process,  and  Mixture  es- 

.  ,>  T.I  sentially  de- 

show  besides,  that  the  exchange  of  the  two  liquids  on  termined  by 

both  sides  of  the  bladder  is  essentially  determined  by  dena!ty<of 
their  unequal  specific  gravities.  As  long  as  the  differ- 
ence in  their  composition  (which  may  here  be  meas- 
ured by  the  specific  gravity)  is  very  great,  the  change 
of  volume  (increase  of  one  and  decrease  of  the  other) 
takes  place  rapidly  ;  but  at  last,  when  this  difference 
becomes  very  small,  the  liquids  mix  without  further 
visible  change  of  volume,  obviously,  because  the  at- 
traction of  the  bladder  to  the  mixtures  on  the  opposite 
sides  does  not  perceptibly  differ,  although  the  specific 
gravities  are  still  somewhat  unequal. 

In  the  ultimate  result,  the  action  of  dissimilar  liquids  The  action  of 
on  the  substance  of  animal  tissues,  in  consequence  of  upon 'animal 
which  their  mixture  is  attended  with  a  change  of  vol-  equivalent 
ume,  appears  to  be  equivalent  to  a  mechanical  press-  changeki 
15 


170       THE  ATTRACTION  OF  LIQUIDS  FOR  MEMBRANES 


procure  un-  ure,  which  is  stronger  from  one   side  than   from   the 

equal  on  op        , 
posite  sides.     Other. 

If  the  tube  (Fig.  9),  which 
is  closed  with  bladder  at  its 
wide  opening,  be  filled  with 
brine  to  the  mark  a,  if  so  much 
mercury  be  then  poured  into 
the  narrow  vertical  part  as  by 
its  pressure  to  cause  brine  to 
begin  to  flow  out  in  fine  drops 
from  the  pores  of  the  bladder, 
and  if  now,  after  removing  so 
much  of  the  mercury  that  the 
efflux  is  no  longer  visible,  we 
place  the  apparatus  in  a  vessel 
with  pure  water,  colored  blue, 
as  in  the  figure,  the  mercury  «= 
does  not  change  its  level ;  and  when,  after  one  or  two 
hours,  we  carefully  remove  the  tube  from  the  water, 
we  find  that  in  the  upper  part  of  the  wide  end  of  the 
tube,  which  contained  colorless  brine,  a  dark  blue  stra- 
tum has  been  formed,  which  floats  on  a  colorless  liq- 
uid. After  a  longer  time,  the  blue  color  spreads  grad- 
ually downwards,  till  at  last  the  brine  acquires  a  uni- 
form blue  tint. 

It  will  readily  be  perceived,  that  the  two  liquids  here 
mix,  as  if  no  pressure  had  been  applied  to  the  brine, 
for  a  mechanical  pressure  exerts  no  influence  on  the 
mixture  ;  but,  in  consequence  of  the  pressure,  the  mix- 
ture takes  place  without  change  of  volume.  The  me- 
chanical pressure  which  the  water,  in  virtue  of  its 
stronger  affinity  for  the  bladder,  exerts  on  the  brine  in 
the  pores  of  the  bladder,  is  held  in  equilibrium  by  the 
column  of  mercury,  and  the  result  is,  that  exactly  as 
much  brine  flows  out  as  water  flows  in. 


IS  EQUIVALENT  TO  A  MECHANICAL  PRESSURE.        171 

Let  us  suppose  the  column  of  mercury  to  be  re-  Additional 

P    ,  .          .        .  ,  example. 

moved,  and  the  rise  of  the  brine  in  the  narrow  tube  is 
explained  at  once.  If  we  close  a  short  tube,  filled  with 
alcohol  or  brine,  with  bladder  at  both  ends  (an  arrange- 
ment which  may  represent  a  cell),  and  suspend  it  in  a 
vessel  of  pure  water,  both  surfaces  of  the  bladder  be- 
come convex  outwards  ;  they  swell,  but  without  burst- 
ing. As  soon  as  the  pressure,  gradually  increasing  by 
the  influx  of  water  into  the  interior  of  the  tube,  is  suf- 
ficient to  keep  in  equilibrium  the  affinity  of  the  water 
for  the  bladder,  and  consequently  its  further  influx,  the 
exchange  goes  on,  for  the  future,  without  change  of 
volume. 

Most  porous  bodies  exhibit  the  phenomena  described  Porous  boti- 

,.  '  ,     .  .  ies  generally 

in  the  preceding  pages,  if  their  pores  are   so  minute  exhibit  sim- 

,   ilar  phenom- 

that  a  feeble  hydrostatic  pressure  is   not   propagated  ena. 
through  them.     These   phenomena  may  be   produced 
with  clay  cells  *  (such  as  are  used  for  galvanic  appa- 

•*  I  consider  it  of  sufficient  importance  to  state  here  that  po-  Among 

„  liquids  ab- 

rous  clay  also  takes  up  unequal  volumes  of  brine   and  water.  S0rbed  by 

In  special  experiments  made  on  this  subject,  cells  of  clay  (mod-  ^g°"|Sa bak" 
erately  ignited  porcelain  biscuit)  were  laid  for  24  hours  in  pure 
water,  then  carefully  dried  externally  with  bibulous  paper,  and 
the  increase  in  weight,  that  is,  the  weight  of  the  absorbed  water, 
carefully  determined.  The  clay  was  then  carefully  dried,  laid 
for  24  hours  in  brine,  and  the  weight  of  the  absorbed  brine  de- 
termined in  like  manner.  In  a  second  series  of  experiments, 
the  clay  cells  were  steeped  in  water  and  brine,  and  placed  in 
the  receiver  of  the  air-pump,  under  a  pressure  of  8  lines  of  mer- 
cury (fds  of  an  inch)  for  24  hours. 

Under  the  ordinary  pressure,  and  in  air,  the  cells  absorbed 

Weight.  Volume. 

Water.     Brine.      Water.    Brine. 

100  parts  of  clay  cell  I.  — 15  4       14.6        15.4       12.2 

II.  — 11.8      11.6        11.8        9.7 
In  vacuo,  the  cells  of  clay  absorbed 

Weight.  Volume. 

Water.    Brine.      Water.     Brine. 

100  parts  of  clay  cell  absorbed    I.  —  16.5       16.8         16.5       14.0 
II. —  13.8      13.8        13.8      11.5 


172  ACTION    OF    LIQUIDS    ON    THE 

ratus)  ;  with  the  lining  membrane  of  the  pods  of  peas 
and  beans  ;  with  the  fine  inner  bark  of  trees ;  with  the 
skin  of  grapes,  of  potatoes,  of  apples  ;  with  the  inner 
membrane  of  the  capsules  of  bladder  senna,  &c.  ;  but 
animal  tissues  surpass  all  others  in  efficacy.  Besides 
their  unequal  affinity,  they  have  an  unequal  absorbent 
power  for  dissimilar  liquids,  by  which  their  action  in 
causing  change  of  volume  during  mixture  is  strength- 
ened. 

Effect  when  When  a  tube,  closed  with  bladder,  and  filled  with 
SnunersetHn  wa^r,  is  immersed  in  alcohol  or  brine,  there  is  pro- 
brine  or  aico-  duced  at  all  points,  where  the  brine  or  the  alcohol 
comes  in  contact  with  bladder  saturated  with  water,  a 
change  in  the  properties  of  the  bladder.  When,  in  the 
open  pores,  the  alcohol  or  brine  mixes  with  the  water 
already  there,  the  absorbent  power  of  the  bladder  for 
the  water  is  diminished ;  a  smaller  volume  of  the  mix- 
ture is  retained  than  of  pure  water;  that  is  to  say, 
water  flows  out  in  the  direction  of  the  alcohol  or 
brine.  This  efflux  is  accompanied  by  a  change  in  the 
volume  of  the  substance  of  the  bladder,  for  that  side  of 
it  which  is  towards  the  alcohol  or  the  brine  contracts  or 
shrinks. 

The  opposite  surfaces  of  an  animal  membrane,  in 
contact  with  dissimilar  liquids,  for  which  they  have  un- 
equal absorbent  power,  are  in  an  unequal  state  of  con- 
traction. This  condition  is  permanent,  as  long  as  the 
liquids  do  not  change  in  their  properties ;  but  it  ceases 
in  consequence  of  mixture,  and  is  again  restored  when, 
by  means  of  the  change  of  place  in  both  the  liquids 
which  are  in  contact  with  the  opposite  surfaces  of  the 
bladder,  the  original  or  any  other  permanent  inequality 
or  difference  of  properties  is  produced. 

Change  in  ^n  a^  cases  where  a  permanent  change  in  the  vol- 

of iwoHqulds  ume  °f  two  liquids,  separated  by  a  membrane,  is  ob- 


MEMBRANE    SEPARATING    THEM.  173 

served  during  their  mixture,  it  is  always  accompanied  separated 
by  a  permanent  difference  in  the  nature  or  properties  brane  is  ac- 
of  the  two  liquids  ;  and  from  this  it  follows,  that  the  ^continual 
molecules  of  the  animal  membrane  must  be,  during  the  ^cmg  the 
mixture,  in  an  alternate  state  of  contraction  and  swell-  0 

ing,  or  dilatation  ;  that  is,  in  a  continual  motion. 

From   what    has   been   stated,    it   appears    that    the  and  depends 

..,,,..,  upon  the  un- 

change  of  volume  of  two  miscible  liquids,  separated  by  equal  anrac- 

.  lion  of  the 

a  membrane,  is  determined  by  the  unequal  capacity  of  membrane 
being  moistened,  or  the  unequal  attraction  of  the  mem-  liquids. 
brane  for  these  liquids.     The  unequal  absorbent  power 
of  the  membrane  for  these  liquids  depends  on  the  dis- 
similar nature  of  the  liquids  or  of  the  substances  dis- 
solved in  them.     An  unequal  proportion  of  the  same 
dissolved  matters  (unequal  concentration)  acts  in  many 
cases  just  as  if  the  liquids  contained  dissimilar  substan- 
ces. 

Although  the  experiments  hitherto  instituted,  and  the 
results  obtained  by  Fischer  (who  first  observed  these 
phenomena),  Magnus,  Dutrochet,  and  others,  admit  of 
no  comparison,  since  the  apparatus  used  by  them 
showed  only  relative  change  of  volume,  yet  a  knowl- 
edge of  some  of  these  results  is  nevertheless  of  impor- 
tance. 

When  the  two  liquids  are  diluted  sulphuric  acid  (of  Effect  of 
sp.  g.  1.093)  and  water,  the  acid,  at  50°  F.,  increases 
in  volume  ;  but  if  the   acid    have  the  specific  gravity 
1.054,  the  volume  of  the  water  increases. 

Diluted  tartaric  acid  (11  parts  of  the  crystallized  acid 
and  89  of  water)  arid  water  mix  through  a  bladder 
without  change  of  volume;  with  more  than  11  per 
cent,  of  acid,  the  volume  of  the  acid  increases  ;  with 
less,  that  of  the  water. 

Solutions  of  animal  gelatine,  gum,  sugar,  and  albu- 
men increase  in  volume  when  separated  by  a  bladder 
15* 


174  CHANGE    OF    VOLUME    IN    LIQUIDS. 

from  water  ;  and  the  increase  of  volume  in  these  dif- 
ferent solutions,  although  of  the  same  specific  gravity, 
is  very  different  indeed.  When  the  specific  gravity  is 
1.07,  the  increase  in  volume  of  the  solution  of  gelatine 
amounts  to  3,  that  of  solution  of  gum  to  5,  of  sugar,  11, 
of  albumen,  12.  When  a  solution  of  sugar  (1  part  of 
sugar  to  16  of  water)  is  separated  by  a  bladder  from 
water,  it  increases  in  volume  ;  but  if  we  add  1  part 
of  oxalic  acid  to  the  sugar,  the  water,  on  the  contrary, 
increases  in  volume.  If  the  amount  of  sugar  in  the  so- 
lution be  doubled,  the  liquids  mix  without  change  of 
volume.  A  solution  of  sugar,  separated  by  bladder 
from  one  of  oxalic  acid,  rises,  in  the  same  time,  3  times 
higher  than  when  separated  from  water.  (Dutrochet.) 
Membranes  From  these  experiments  we  obtain,  as  a  universal 

have  less  .  . 

power  of  ah-   result  (which,  however,  requires  confirmation),  that  an 

sorbing  solu-         .        .  .  „      , 

tionofaibu-   animal  membrane  possesses  a  less  power  or  absorption 
ail  other  sub-  for  solution  of  albumen  than  for  all  other  organic  sub- 
stances ;  and  that  a  small  amount  of  mineral  or  organic 
Effect  of  add-  acids  increases  the  power  of  transudation  of  water,  as 

well  as  of  the  solutions  of  many  organic  substances.* 
Causes  which       The  rapidity  of  mixture  of  two  liquids,  separated  by 
pidity  of       a   membrane,  depends  on  the  thickness  of  the  mem- 
brane, and  stands  in  direct  proportion  to  the  velocity 
with  which  the  mixture  formed  in  the  pores  and  on  both 
surfaces  of  the  bladder  changes  its  place,  and  the  orig- 


*  In  order  not  to  be  misled  in  such  experiments,  we  must 
avoid  the  employment  of  all  those  liquids  which  alter  the  mem- 
brane in  its  chemical  properties.  Such  are,  for  example,  acids 
of  a  certain  concentration,  nitrate  of  silver,  salts  of  lead,  chlo- 
ride of  gold,  chloride  of  tin,  chromic  acid,  bichromate  of  potash, 
tannic  acid,  &c.  Even  in  water,  the  properties  of  membranes 
generally  undergo  a  change  after  some  days ;  they  then  propagate 
a  far  weaker  hydrostatic  pressure  through  their  pores,  and  are  no 
longer  fit  for  such  experiments. 


CAUSES    OF    ABSORPTION.  175 

inal  difference  in  the  quality, of  the  two  liquids  is  re- 
newed. 

If  we  suppose  a  tube,  formed  of  a  membrane  (an  in-  Action  of  in- 
testine, for  example),  and  filled  with  water,  and  if  we 
assume  that  a  current  of  saline  solution  flows  round 
this  tube,  in  consequence  of  a  mechanical  force,  the 
increase  of  volume  of  the  brine  (the  passage  into  it  of 
a  certain  amount  of  water)  will  be  effected  in  a  far 
shorter  time  than  if  the  brine  were  not  in  motion. 

The  velocity  of  transference  will  diminish  with  the  Transference 

,  diminishes 

amount  of  difference   in  properties   between   the   two  with  the  dif- 

,  -  «        , .  v       ference  of 

liquids    (the    different  amount  or  percentage  of  salt) ;  properties 
it  will  be  greatest  at  firstn  and  diminish  as  the  dilution  nqJidT  l 
of  the  brine  increases,  in  proportion,  that  is  to  say,  as 
water  is  transferred  from  the  contents  of  the  tube  to  the 
liquid  without. 

The  greatest  effect,  therefore,  must  occur  and  be  per-  Tbe  greatest 
manent,  when  the  water  transferred  to  the  brine  is  con-  ^^  theUrs 
tinually  again  removed  from  it,  that  is,  when  the  con-  JJn^bXST 
centration  of  the  brine  is  kept  uniform.     To  this  end,  if  JJrmptun' 
we  suppose  the  membrane  to  be  difficultly  permeable 
for  one  liquid,  while  the  other  is  easily  taken  up  into  its 
pores,  and  if  we  reflect  that  this  second  liquid,  on  en- 
tering into  the  pores  of  the  bladder,  in  virtue  of  the  at- 
traction of  their  walls  for  it,  acquires  a  certain  velocity 
which  permits  it  to  pass  beyond  the  extremities  of  the 
canal  or  of  the   pores,  so  as  entirely  to  fill  the  pores, 
and  to  come  in  direct  contact  with  the  liquid  on  the  out- 
side   of  the    pores,   it  follows,  that,  when  this  second 
liquid  moves  past  the  pores  with  a  certain  velocity,  the 
absorbed  liquid  must  follow  it  during  the  mixture,  and 
there  must  take  place  a  rapid  transference  of  the  sec- 
ond liquid  to  the  first,  —  a  true  suction,  as  if  by  a  pump. 

The  animal  body  is  an  example  of  an  apparatus  of  The  animal 
this  kind  in  the  most  perfect  form.     The  bloodvessels  Paratu"ap 


176  EFFECTS    PRODUCED    BY    DRINKING 

contain  a  liquid  for  which  their  walls  are,  in  the  normal 
state,  far  less  permeable  than  for  all  the  other  fluids  of 
the  body.  The  blood  moves  in  them  with  a  certain 
velocity,  and  is  kept  at  all  times  in  a  nearly  uniform 
state  of  concentration  by  a  special  apparatus,  namely, 
the  urinary  organs. 
Absorption  The  whole  intestinal  canal  is  surrounded  with  this 

of  the  liquids 

into  the  in-    system  of  bloodvessels,  and  all   the    animal   fluids,   in 

testmes  from     * 

the  blood.  so  far  as  they  are  capable  of  being  taken  up  by  the 
parietes  of  the  intestinal  canal,  and  of  the  blood- 
vessels situated  around  it,  are  rapidly  mixed  with  the 
blood.  The  volume  of  the  blood  increases,  if  no  com- 
pensation is  effected  by  means  of  the  kidneys  ;  and  the 
intestine  is  emptied  of  the  liquids  contained  in  it.  The 
intestinal  glands,  through  which  this  transference  is 
effected,  and  each  of  which  represents  a  similar  appa- 
ratus of  suction,  contain,  within  them,  two  systems  of 
canals,  —  bloodvessels  and  lacteals;  the  bloodvessels 
are  placed  next  to  the  external  absorbent  surface,  the 
lacteals  chiefly  occupy  the  central  part  of  the  gland. 
The  liquids  circulating  in  these  two  systems  have  very 
unequal  velocities,  and  as  the  blood  moves  much  faster 
in  the  bloodvessels,  we  perceive  how  it  happens  that 
the  fluids  of  the  intestine  are  chiefly  (in  quantity  and 
in  velocity)  taken  up  into  the  circulation. 

Effects  pro          The  difference  in  the  absorbent  power  of  the  parietes 

organism  by   of  the  intestinal  canal  for  liquids  which  contain  unequal 

saline soiu-     amounts  of  dissolved  matters  is  easily  observed  in  the 

effects  produced  on  the  organism  by  water  and  saline 

solutions. 

If  we  take,  while  fasting,  every  ten  minutes,  a  glass 
of  ordinary  spring  water,  the  saline  contents  of  which 
are  much  less  than  those  of  the  blood,  there  occurs,  af- 
ter the  second  glass  (each  glass  containing  4  ounces), 
an  evacuation  of  colored  urine,  the  weight  of  which  is 


WATER    AND    SALINE    SOLUTIONS.  177 

very  nearly  equal  to  that  of  the  first  glass  ;  and  after 
taking,  in  this  way,  20  such  glasses  of  water,  we  have 
had  19  evacuations  of  urine,  the  last  of  which  is  color- 
less, and  contains  hardly  more  saline  matter  than  the 
spring  water. 

If  we  make  the  same  experiment  with  a  water  con-  Drinking  sea- 
taining  as  much  saline  matter  as  the  blood  (f  to  1  per 
cent,  of  sea  salt),  there  is  no  unusual  discharge  of 
urine,  and  it  is  difficult  to  drink  more  than  three  glasses 
of  such  water.  A  sense  of  repletion,  pressure,  and 
weight  of  the  stomach  point  out,  that  water  as  strongly 
charged  with  saline  matter  as  the  blood  requires  a  long- 
er time  for  its  absorption  into  the  bloodvessels. 

Finally,  if  we  drink  a  solution  containing  rather  more  Solutions 
salt  than  the  blood,  a  more  or  less  decided  catharsis  en-  more  saitg 

than  the 
blood. 


The  action  of  solution  of  salt  is  of  three  kinds,  ac- 
cording to  the  proportion  of  salt.  Spring  water  is  taken 
up  into  the  bloodvessels  with  great  rapidity  ;  while 
these  vessels  exhibit  a  very  small  power  of  absorption 
for  water  containing  the  same  proportion  of  salt  as  the 
blood  does  ;  and  a  still  more  strongly  saline  solution 
passes  out  of  the  body,  —  not  through  the  kidneys,  but 
through  the  intestinal  canal. 

Saline  solutions  and  water,  given  in  the  form  of  ene-  Enemata  in 

........  .  ._  water  act  as 

mata,  exhibit  similar  phenomena  in  the  rectum.     Pure  saline  soiu- 

water  is  very  rapidly  absorbed,  and  excreted  through 

the  urinary  passages.     If  we  add  to  the  water  colored 

or  odorous  matters,  these  appear  more  or  less  changed 

in  the  urine.     When  a  small  quantity  of  ferrocyanide 

of  potassium  is  added,  its  presence  in  the  urine  is  very 

soon  detected  by  chloride  of  iron,  which  forms  with  it 

Prussian  blue.     Of  concentrated  solutions,  far  less  is  ab- 

sorbed in  the  same  time  than  of  diluted  ;  in  most  cases, 

they  mix  with  solid  matters  collected  in  the  rectum,  and 

are  expelled  in  the  form  of  a  watery  dejection. 


178  MEMBRANES    PROBABLY    EXERT 

Action  of  All  salts  do  not  act  alike  in  this  respect.     In  equal 

Glauber  and       ,  . 

Epsom  salts  doses,  the  purgative  action  of  Glauber  salt  and  Epsom 
with  that  of  salt  is  far  stronger  than  that  of  sea  salt ;  and  their  power 
of  being  absorbed  by  animal  membranes  appears  to  be  in 
the  inverse  ratio  of  this  effect.  It  is  hardly  necessary 
particularly  to  point  out  that  an  explanation  of  the  action 
of  purgatives  in  general  cannot  be  included  in  the  above- 
described  action  of  saline  solutions  on  the  organism. 
The  example  which  has  been  given  is  intended  to  illus- 
trate a  physical  property  common  to  a  large  number  of 
salts,  and  apparently  independent  of  the  nature  of  the 
acid  or  base  of  the  salt ;  for  chloride  of  calcium,  chlo- 
ride of  magnesium,  bitartrate  of  potash,  tartrate  of  potash 
and  soda,  phosphate  of  soda,  and  certain  doses  of  tartar 
emetic,  show  the  same  action  as  sea  salt,  Glauber  salt, 
and  Epsom  salt,  although  the  bases  and  acids  in  these 
different  salts  are  not  the  same. 

Solutions  of  cane  sugar,  grape  sugar,  sugar  of  milk, 
and  gum,  exhibit,  when  separated  from  water  by  an 
animal  membrane,  phenomena  similar  to  those  exhibited 
by  the  above-named  solutions  of  mineral  salts,  without 
causing  in  the  living  body  a  purgative  action,  when  of 
equal  concentration.  The  cause  of  this  difference  may 
be,  that  the  mineral  salts,  in  their  passage  through  the 
intestinal  canal  and  through  the  blood,  are  not  essential- 
ly altered  in  their  composition,  while  these  organic  sub- 
stances, in  contact  with  the  parietes  of  the  stomach,  and 
under  the  influence  of  the  gastric  juice,  suffer  a  very 
rapid  change,  by  which  the  action  which  they  have  out 
of  the  body  is  arrested. 

Since  the  chemical  nature  and  the  mechanical  char- 
acter of  membranes  and  skins  exert  the  greatest  influ- 
ence on  the  distribution  of  the  fluids  in  the  animal  body, 
the  relations  of  each  membrane  presenting  any  peculi- 
arity of  structure,  or  of  the  different  glands  and  systems 


AN    IMPORTANT    INFLUENCE    ON    SECRETIONS.         179 

of  vessels,  deserve  to  be  investigated  by  careful  experi- 
ment ;  and  it  might  very  likely  be  found,  that,  in  the 
secretion  of  the  milk,  the  bile,  the  urine,  the  sweat,  &c., 
the  membranes  and  cell-walls  play  a  far  more  impor- 
tant part  than  we  are  inclined  to  ascribe  to  them ;  that, 
besides  their  physical  properties,  they  possess  certain 
chemical  properties,  by  which  they  are  enabled  to  pro- 
duce decompositions  and  combinations,  true  analyses ; 
and  if  this  were  ascertained,  the  influence  of  chemical 
agents,  of  remedies,  and  of  poisons  on  those  properties 
would  be  at  once  explained. 

The  phenomena  described  in  the  preceding  pages  are  Thephenom- 
observed,  not  in  the  gelatinous  tissues  alone,  but  also,  fined  to  the 
apparently,  in  many  other  structures  of  the  animal  body,  ussues°U* 
which  cannot  be  reckoned  as  belonging  to  that  class. 

If  we  tie  moist  paper  over  the  open  end  of  a  cylindri-  Coagulated 

.         .  .  albumen  acts 

cal  tube,  and,  after  pouring  in  above  the  paper  white  of  like  thin 

.  7  membrane. 

egg  to  the  height  of  a  few  lines,  place  that  end  of  the  tube 
in  boiling  water,  the  albumen  is  coagulated,  and  when  the 
paper  is  removed,  we  have  a  tube  closed  with  an  accu- 
rately fitting  plug  of  coagulated  albumen,  which  allows 
neither  water  nor  brine  to  run  through.  If  the  tube  be 
now  filled  to  one  half  with  brine,  and  immersed  in  pure 
water,  as  in  Fig.  4,  the  brine  is  seen  gradually  to  rise ; 
and  in  three  or  four  days  it  increases  by  from  J  to  £  of 
its  volume,  exactly  as  if  the  tube  had  been  closed  with 
a  very  thick  membrane. 

Influence  of  the  Cutaneous  Evaporation  on  the  Motion 
of  the  Fluids  of  the  Animal  Body. 

When  a  tube,  about  30  inches  long,  bent  in  the  form  influence  of 

•  •  cutaneous 

of  a  knee,  and  widened  at  one  end,  is  tied  over  at  that  evaporation 

.  .  on  the  motion 

end  with  a  piece  of  moist  ox-bladder,  the  bladder  now  of  the  animal 
thoroughly  dried,  and  the  tube  filled  with  mercury  and  JU 
inverted,  so  that  the  open  narrow  end  stands  in  a  cup 


180 


INFLUENCE  OF  THE  CUTANEOUS 


Experi- 
ments. 


of  mercury,  the  mercury  in  the  tube  falls  to  about  27 
inches  (Hessian),  and  remains,  if  the  bladder  have  no 
flow,  at  that  height,  rising  and  falling  as  the  mercury 
does  in  a  barometer. 

No  air  passes  through  the  dry  bladder  into  the  Torri- 
cellian vacuum  thus  produced.  When,  by  proper  ma- 
nipulation, we  have  allowed  to  pass  out  as  much  as  can 
be  removed  of  the  air  still  contained  in  the  tube,  we 
have  in  this  arrangement  a  barometer,  containing  no 
more  air  than  would  be  found  in  one  made  with  a  simi- 
lar tube  hermetically  sealed  at  the  wide  end,  provided 
the  mercury  in  the  latter  had  not  been  boiled  in  the 
tube  to  expel  the  last  traces  of  air.  By  the  desiccation 
of  the  bladder,  its  pores,  which  allowed  a  passage  to 
water,  brine,  oil,  or  even  mercury,  have  obviously  been 
closed  by  the  adhesion  of  the  successive  layers  of  mem- 
brane, which  perhaps  cross  each  other,  so  that  the 
bladder  is  not  more  permeable  for  the  particles  of  air 
than  a  slice  of  horn  of  the  same  thickness. 

If  we  introduce  wa-  Fig<  10. 

ter  into  the  tube  in  the 
position  Fig.  10,  to 
the  line  marked  Z>, 
and,  after  filling  the 
narrow  part  of  the 
tube  with  mercury, 
invert  it  in  a  vessel 
of  mercury,  Fig.  11, 
we  observe  a  number 
of  minute  bubbles  of 
air  passing  through 
the  moist  bladder  into 
the  tube.  The  mer- 
cury falls  to  a  certain 
point,  which  is  higher 


Fig.  11. 


EVAPORATION    ON    THE    MOTION    OF    THE    FLUIDS.     181 

or  lower  according  to  the  thickness  of  the  bladder  ;  it 
stands  at  a  lower  level  with  a  thin  membrane  than  with  a 
thick  one.  When  a  single  layer  of  ox-bladder  is  used, 
it  falls  to  12  inches  (above  the  level  of  the  mercury  in 
the  vessel) ;  with  a  double  layer,  it  stands  at  from  22  to 
24  inches. 

If  we  take  care  to  allow  the  water  standing  above 
the  mercury  to  enter  the  wide  part  of  the  tube,  so  that 
the  bladder  is  kept  at  all  times  covered  with  water,  the 
mercury  remains  stationary  at  the  same  level.  If,  for 
example,  it  stood  at  12  inches,  it  remains  there,  al- 
though the  quantity  of  water  is  constantly  diminishing 
by  evaporation  from  the  bladder ;  and  it  maintains  its 
level,  even  after  all  the  water  has  disappeared. 

The  height  of  the  mercury  in  the  narrow  tube  is  an 
exact  measure  of  the  pressure  acting  on  the  surface  of 
the  bladder.  The  pressure  in  the  inside  of  the  tube  is 
less  than  the  existing  pressure  of  the  atmosphere  outside 
by  the  height  of  that  column  of  mercury. 

This  difference  of  level  between  the  mercury  in  the 
vessel  and  that  in  the  tube  is  the  limit  of  the  pressure 
under  which  air  passes  into  the  water  through  the  pores 
of  the  bladder  ;  or  under  which  the  molecules  of  water 
in  the  pores  are  displaced  by  the  molecules  of  air. 

If  we  fill  the  tube  entirely  with  water,  and  place  the 
narrow  end  in  mercury,  while  the  wide  end,  closed  with 
bladder,  is  exposed  to  the  air,  the  mercury  rises  in  the 
narrow  limb,  and  at  last  reaches  a  point  identical  with 
that  to  which  it  fell  in  the  preceding  experiment.  For 
each  specimen  of  bladder,  according  to  its  thickness, 
the  level  to  which  the  mercury  reaches  is  of  course  dif- 
ferent. 

When  the  diameter  of  the  wide  part  of  the  tube, 
which  is  closed  with  bladder,  is  12  millimetres,  and  that 
of  the  narrow  tube  1  millimetre,  the  mercury  rises,  with 
16 


182  EVAPORATION    THROUGH    MEMBRANES. 

ox-bladder,  according  to  the  temperature  and  the  hy- 
grometric  condition  of  the  air,  to  from  22  to  65  milli- 
metres in  one  hour. 

The  cause  of  the  rise  of  the  mercury  in  this  experi- 
ment hardly  requires  a  special  explanation. 

Explanation.  The  bladder  is  penetrated  with  water,  covered  on  one 
side  with  water,  and  on  the  other  in  contact  with  a 
space  (the  air)  not  saturated  with  aqueous  vapor.  The 
water  contained  in  the  pores  of  the  side  of  the  bladder 
turned  towards  the  air  evaporates  ;  the  space  which  it 
had  occupied  in  the  pores  is  filled  with  successive  por- 
tions of  water  from  within,  in  virtue  of  the  attraction 
of  the  substance  of  the  pores  for  water.  The  volume 
of  the  water  in  the  tube  diminishes,  and  thus  a  vacuum 
arises,  in  which  the  mercury  is  forced  to  rise  by  the  at- 
mospheric pressure.  The  space  formerly  occupied  by 
the  water  which  has  evaporated  is  now  filled  with  mer- 
cury. 

When  the  mercury  has  reached  a  permanent  level, 
the  external  pressure,  which  acts  on  the  water  in  the 
pores  of  the  bladder  (and  which  tends  to  displace  the 
particles  of  water)  is  obviously  equal,  before  air  enters, 
to  the  attraction  which  the  substance  of  the  bladder  has 
for  the  particles  of  water,  and  these  last  to  each  other. 
Were  the  attraction  less,  air  would  enter,  and  the  parti- 
cles of  water  could  not  maintain  their  position. 

The  rise  of  the  mercury,  or  its  motion  towards  the 
surface  of  the  bladder,  that  is,  towards  the  point  where 
evaporation  is  going  on,  is  the  result  of  a  difference  of 
atmospheric  pressure,  determined  by  the  evaporation  of 
the  water,  or  of  the  liquid  which  penetrates  through  the 
bladder,  and  by  the  absorbent  power  of  the  bladder  for 
that  liquid. 

One  chief  condition  of  the  efficiency  of  a  bladder,  in 
regard  to  the  rise  of  a  column  of  liquid,  is,  that  it  is  kept 


INFLUENCE  OF  THE  PRESSURE  OF  THE  AIR.    183 

constantly  in  contact  with  the  liquid,  for  without  this 
contact  the  absorbent  power  cannot  manifest  itself. 

By  the  evaporation,  a  continual  efflux  of  water,  in  the 
form  of  vapor,  towards  the  side  on  which  the  air  lies,  is 
produced  ;  and  by  the  capillary  action  of  the  bladder  on 
the  other  side,  water  is  absorbed  and  retained  with  a 
force  which  counterpoises  12  or  more  inches  of  mercu- 
ry, according  to  the  thickness  of  the  bladder. 

Now,  since  the  rise  of  the  mercury  is  an  effect  of  the  Dependence 
atmospheric  pressure,  it  is  plain  that  the  height  to  which  state  of  the 

,  .  IT,  -1  barometer. 

the  mercury  rises  must  depend  to  a  certain  degree  on 
the  state  of  the  barometer. 

In  a  tube,  filled  with  water,  and  closed  with  bladder, 
the  absorbent  force  of  which  is  equal  to  the  pressure  of 
a  column  of  12  inches  of  mercury,  the  mercury  rises 
by  evaporation  to  the  height  of  12  inches,  as  long  as  a 
column  of  12  inches  of  mercury  can  be  sustained  by 
the  external  atmospheric  pressure.  If  this  external 
pressure  fall  below  that  limit,  the  mercury  in  the  evap- 
oration tube  falls  to  the  same  extent,  and  if  there  be 
water  above  the  mercury,  this  water  separates  from  the 
bladder. 

This  property  of  bladder,  therefore,  would  appear 
unaltered  at  an  elevation  at  which  the  barometer  should 
stand  at  12  inches  ;  at  a  still  greater  elevation,  on  the 
contrary,  the  liquid  would  separate  from  the  bladder. 

The    external    pressure    has    no    influence    on    the  The  pressure 

„.    .  ...  «    ,       of  the  air  has 

amount  or  the  water  evaporating  in  the  pores  or  the  no  influence 
bladder  ;  that  amount  depends  on  the  hygrometric  state  amount  of 
of  the  surrounding  air,  and  on  the  temperature.     In  a  ev 
rarefied  air  (provided  it  can  take  up  moisture),  evap- 
oration goes  on  more  rapidly  than  in  a  denser  air  ;  and 
hence  it  is  clear,  that,  at  certain  elevations,  the  effect  of 
the  bladder  on  the  level  of  the  liquid  is  more  quickly 
produced  than  at  the  level  of  the  sea.     The  amount  of 


184  WATER    PASSES    MORE    EASILY 

water  which  evaporates  is  directly  proportional  to  the 
surrounding  space,  and  to  the  temperature  and  corre- 
sponding tension  of  the  liquid. 

When  the  tube,  Fig.  10,  is  filled  with  water  to  Z>, 
then  entirely  filled  with  mercury,  and  inverted  in  mer- 
cury, the  mercury,  as  we  have  seen,  assumes  a  fixed 
level.  If  now  we  keep  the  upper  or  wide  end  of  the 
tube,  which  is  closed  with  bladder,  immersed  in  a  ves- 
sel of  water,  Fig.  12,  we  shall  Fig.  12. 
find,  after  a  short  time,  that  the 
mercury  sinks  in  the  narrow 
tube.  If  its  level  has  been  12 
inches  above  that  of  the  mer- 
cury in  the  vessel,  it  sinks 
when  the  bladder  is  put  into 
water,  3  or  4  inches  for  exam- 
ple, and  remains  stationary  at 
8  or  9  inches,  without  sinking 
further  for  the  next  12  hours. 
The  sinking  of  the  mercury  is 
caused  by  water  being  forced 
through  the  bladder  into  the 
tube,  in  virtue  of  the  existence 
of  an  external  pressure  greater 
than  the  pressure  on  the  inside  of  the  tube. 

To  displace  the  aqueous  particles  in  the  pores  of  the 
Permeability  bladder  by  other  aqueous  particles  requires  obviously  a 

of  bladder  t  11  .if 

greater  to  much  smaller  pressure  than  is  necessary  to  displace 
tTafr.  '  them  by  particles  of  air.  In  the  one  case,  where  both 
surfaces  of  the  bladder  are  in  contact  with  the  liquid, 
the  attractive  force  (that  of  the  bladder  for  the  water 
and  of  the  water  for  the  bladder)  is  equal  on  both  sides ; 
but  not  so  in  the  other  case,  where  one  side  of  the 
bladder  is  in  contact  with  air.  If  the  bladder  had  the 
same  absorbent  power  for  the  particles  of  air  as  for 


THAN    AIR   THROUGH    MOIST    MEMBRANES.  185 

those  of  water,  the  particles  of  air  and  water  would 
pass  through  the  bladder  under  the  same  pressure  ; 
the  experiment  shows,  that  the  absorbent  power  and 
permeability  of  the  bladder  for  air  are  far  less  than  for 
water.  Hence  it  comes  to  pass,  that  when,  with  a 
given  portion  of  bladder,  in  the  apparatus,  Fig.  11, 
mercury  is  raised  by  evaporation  to  a  height  of  12 
inches,  less  than  12  inches  of  mercury  are  required,  in 
the  apparatus,  Fig.  1,  to  cause  water  to  pass  through 
the  bladder. 

Fig.  13.  When  the  tube  (Fig.  13)  is  filled  with  Experiments 

water,  closed  with  bladder  at  both  ends,  clo^edatboth 
and  exposed  to  evaporation,  the  bladders  membrane; 
in  a  short  time  become  concave,  that  is, 
they  are  pressed  inwards.  As  the  evap- 
oration of  the  water  through  the  moist 
surfaces  of  the  bladder  proceeds,  there 
is  formed  in  the  upper  part  of  the  tube  a 
vacuum,  which  is  filled  with  aqueous  va- 
por, and  which  continues  to  increase. 
The  place  of  the  water  which  evap- 
orates is,  as  in  the  experiments  previously  described, 
gradually  occupied  by  air,  which  enters  the  tube 
through  the  bladder. 

It  is  evident,  that  when  air  enters  the  tube  (Fig.  13), 
the  pressure  on  the  surface  of  the  bladder  is  equal  to 
the  absorbent  force  of  that  bladder  for  the  water.  In 
the  apparatus,  Fig.  11,  with  the  same  bladder,  the  mer- 
cury might  have  been  raised,  in  consequence  of  the 
evaporation,  to  a  height  of  4,  6,  12,  or  more  inches, 
according  to  the  thickness  of  the  membrane. 

When  the  longer  limb  of   the   bent  tube,  after   it  with  one  end 
has  been  filled  with  water,  and  closed  at  both  ends  tube  filled 
with  bladder,  is  placed  in  a  vessel  containing  brine, 
and  exposed  to  evaporate  in  the  air,  as  in  Fig.  14, 
16* 


186 


EVAPORATION    THROUGH    MEMBRANES. 


with  one  end 
of  the  tube 
in  bile  ; 


with  one 
end  in  oil. 


Effect  of  a 
series  of 
short  tubes, 
closed  at  both 
ends  with 
membrane, 
and  connect- 
ed with  each 
other. 


Motion  of 
liquid  is 
toward  the 
surface  from 
which   evap- 


it  is  plain  that  when  the  atmospheric 
pressure,  increasing  in  consequence  of 
the  evaporation  of  the  water  on  both 
the  surfaces  of  the  bladder,  reaches 
the  point  at  which  the  brine  flows 
through  the  pores  of  the  bladder, 
then  the  place  of  the  water  which 
evaporates  is  occupied  by  brine. 

In  fact,  when  the  brine  is  colored 
blue,  we  observe,  after  a  few  hours, 
that  a  blue  stratum  forms  within  the 
tube,  which  constantly  increases,  till  at  last  the  vessel 
of  brine  is  emptied,  and  the  tube  is  entirely  filled  with 
brine. 

If  the  longer  limb  be  immersed  in  bile  instead  of 
brine,  the  tube  fills  with  bile,  and  if  we  employ,  for 
closing  one  end,  a  membrane  rather  thinner  than  we 
use  for  the  other,  from  which  the  evaporation  takes 
place,  and  then  place  the  end  with  the  thinner  mem- 
brane in  oil  (oil  of  marrow),  the  tube  gradually  fills 
with  oil. 

In  all  these  cases,  no  air  enters  the  tube,  which  con- 
tinues full  of  liquid,  as  it  was  at  first. 

If  we  connect  the  evaporation  tube 
by  collars  of  caoutchouc  with  short 
bits  of  tube  (Fig.  15),  full  of  water, 
and  tied  with  bladder  at  both  ends  ; 
and  if  we  immerse  the  last  bit  of 
tube  in  brine,  urine,  oil,  &c.,  all 
these  cells,  and  at  last  the  evapora- 
tion tube  itself,  become  gradually 
filled  with  brine,  urine,  oil,  &c. 

The  most  general  expression  for 
these  experiments  and  results  is  this  ; 
—  that  all  liquids,  which  are  in  con- 


Fig.  15. 


IMPORTANCE  OF  CUTANEOUS  TRANSPIRATION.   187 

nection  with  a  membrane  from  the  surface  of  which  oration  takes 
evaporation  can  take  place,  must  acquire  motion  towards  p 
that  membrane. 

The  amount  of  this  motion  is  directly  proportional  to 
the  rapidity  of  evaporation,  and  consequently  to  the 
temperature  and  hygrometric  state  of  the  atmosphere. 

That  the  skin  of  animals,  and  the  cutaneous  tran-  influence  of 
spiration,  as  well  as  the  evaporation  from  the  internal  cutan^ousand 
surface  of  the  lungs,  exert  an  important  influence  on  ^n^h?1^ 
the  vital  processes,  and  thereby  on  the  state  of  health,  health- 
has  been  admitted  by  physicians  ever  since  medicine 
has  existed  ;  but  no  one  has  hitherto  ascertained  pre- 
cisely in  what  way  this  happens. 

From  what  has  gone  before,  it  can  hardly  be  doubt-  The  cmane- 

.  .  ous  evapora- 

ed,  that  one  of  the  most  important  functions  of  the  tion  has  an 

,  .  •          •        i         i  i  •    i     •         i          •        i  •         important 

skin  consists  m  the  share  which  it  takes  in  the  motion  share  in  caus- 
and  distribution  of  the  fluids  of  the  body.  tion  oAhe0 

The  surface  of  the  body  of  a  number  of  animals 
consists  of  a  covering  or  skin  permeable  for  liquids, 
from  which,  when,  as  in  the  case  of  the  lung,  it  is  in 
contact  with  the  atmosphere,  an  evaporation  of  water, 
according  to  the  hygrometric  state  and  temperature  of 
the  air,  constantly  goes  on. 

If  we  now  keep  in  mind,  that  every  part  of  the  body 
has  to  sustain  the  pressure  of  the  atmosphere,  and  that 
the  gaseous  fluids  and  liquids  contained  in  the  body 
oppose  to  this  pressure  a  perfectly  equal  resistance,  it  is 
clear,  that,  by  the  evaporation  of  the  skin  and  lungs, 
and  in  consequence  of  the  absorbent  power  of  the  skin 
for  the  liquid  in  contact  with  it,  a  difference  in  the  press- 
ure below  the  surface  of  the  evaporating  skin  occurs. 
The  external  pressure  increases,  and  in  an  equal  de- 
gree the  pressure  from  within  towards  the  skin.  If 
now  the  structure  of  the  cutaneous  surface  does  not 
permit  a  diminution  of  its  volume,  a  compression  (in 


188     EFFECTS  OF  CUTANEOUS  EVAPORATION. 

consequence  of  the  loss  of  liquid  by  evaporation),  it  is 
obvious  that  an  equalization  of  this  difference  in  press- 
ure can  only  take  place  from  within  outwards  ;  first 
from  within,  and  especially  from  those  parts  which 
are  in  closest  contact  with  the  atmosphere,  and  which 
offer  the  least  resistance  to  the  action  of  the  external 
pressure. 

Evaporation        Hence  it  follows,  that  the  fluids  of  the  body,  in  con- 
causes  the 
fluids  of  the  sequence  of  the  cutaneous  and  pulmonary  transpira- 

bodytomove     .  .  .  .  .  .     '          - 

towards  the    tion,  acquire  a  motion   towards  the   skin   and   lungs, 
fungs. n         which   must  be  accelerated  by  the  circulation  of  the 

blood. 
Change  in          By  this  evaporation,  the  laws  of  the  mixture  of  dis- 

the  laws  of        .      .,,..,  ,    ,  , 

mixture  of     similar  liquids,  separated  by  a  membrane,  must  be  es- 
liquids  by      sentially  modified.     The  passage  of  the  food  dissolved 

evaporation.    ....  .          i/>ii  i    • 

in  the  alimentary  canal,  and  of  the  lymph  into  the  blood- 
vessels, the  expulsion  of  the  nutritive  fluid  out  of  the 
minuter  bloodvessels,  the  uniform  distribution  of  these 
fluids  in  the  body,  the  absorbent  power  of  the  mem- 
branes and  skins,  which,  under  the  actual  pressure,  are 
permeable  for  the  liquids  in  contact  with  them,  are 
under  the  influence  of  the  difference  in  the  atmospher- 
ical pressure,  which  is  caused  by  the  evaporation  of  the 
fluids  of  the  skin  and  lungs. 

Effects  of  dry  The  juices  and  fluids  of  the  body  distribute  them- 
andIof1eieva'  selves,  according  to  the  thickness  of  the  walls  of  the 
vessels,  and  their  permeability  for  these  fluids,  uni- 
formly through  the  whole  body ;  and  the  influence 
which  a  residence  in  dry  or  in  moist  air,  at  great  ele- 
vations or  at  the  level  of  the  sea,  may  exert  on  the 
health,  in  so  far  as  the  evaporation  may  thus  be  accel- 
erated or  retarded,  requires  no  special  explanation ; 
while,  on  the  other  hand,  the  suppression  of  the  cuta- 
neous transpiration  must  be  followed  by  a  disturbance 
of  this  motion,  in  consequence  of  which  the  normal 
process  is  changed  where  this  occurs. 


EFFECTS  OF  CUTANEOUS  EVAPORATION.     189 

The  pressure,  which,  in  consequence  of  the  evapora-  The  pregsure 
tion,  urges  the  fluids  within  the  body  to  move  towards  ]j[^sg  the 
the   skin,  is,  as  may  readily  be  understood,  equal  to  g^Jf^enoai 
the  difference  of  pressure  acting  on  the  surface  of  the 


ure  acting 
on  the  sur- 

From  the  experiment,  Fig.  13,  it  is  plain,  that  when  ^of  lhe 
one  of  the  two  surfaces  of  bladder  at  the  ends  of  the 
tube,  Fig.  12,  is  exposed  to  atmospheric  evaporation, 
while  the  other  end  is  moistened  with  water,  brine,  or 

011,  these  liquids  are  rapidly  absorbed  by  the  mem- 
brane, that  is,  are  forced  in  by  the   external  atmos- 
pheric  pressure,  and  it  is  not  less  obvious,  that   the 
same  thing  takes  place  with  the  liquid  with  which  one 
of  the  two  evaporating  surfaces  has  been  moistened  in 
the    middle    only ;    while    the    evaporation    continues 
around  the  moistened  spot. 

If,  therefore,  we  moisten  with  a  liquid  the  surface  of  if  we  moisten 

.,1  ,.  -,  .  .    ,     Al        v       .j    .      /.          j   the  skin,  the 

the  evaporating  skin  at  any  point,  the  liquid  is  forced  liquids  are 
inwards  by  the  external  pressure.  externa1/1 

Let  us  suppose  any  part  of  the  skin  to  be  rubbed  pre£ 
with  fat,  the  transpiration  ceases  at  that  part.     If  now  Rubbed  with 
the  skin  around  the  part  is  in  its  normal  activity,  if,  cease^to8^111 
therefore,  in  the  surrounding  parts  liquid  is  constantly  transPire- 
passing  off  by  evaporation,  the  fat  must  be  urged,  by 
the  unequal  pressure  thus  arising,  towards  these  parts, 
or  it  is  absorbed,  just  as  water,  in  the  apparatus,  Fig. 

12,  is  absorbed,  when  in  consequence  of  evaporation  a 
difference  between  the  internal  and  external  pressure 
has  arisen.     If  the  whole  skin  were  covered  with  fat, 
the  absorption  would   be  effected   by  the   pulmonary 
evaporation. 

The  blistering  of  the  skin,  and  the  sun-burning,  to 
which  men  are  exposed  at  great  elevations,  arise  from 
the  extraordinary  dryness  of  the  air,  the  increased 
evaporation,  and  the  pressure  by  which  the  fluids  filling 
the  vessels  are  forced  towards  the  surface. 


190        EXPERIMENTS  OF  HALES  ON  THE 

causes  of  the       Several  causes  contribute  jointly  to  the  appearance 
sweat.  of  the  sweat,  —  to  the  efflux  of  fluid  from  the  pores  of 

the  skin.  One  of  these  obviously  depends  on  the  ve- 
locity which  the  fluid  set  in  motion  by  evaporation  or 
by  a  mechanical  cause  acquires  from  the  accelerated 
motion  of  the  blood.  In  consequence  of  this  velocity, 
the  fluid  moves  out  beyond  the  limits  of  the  absorbing 
membrane  or  skin. 

Fishes  die  in       The  changes  of  the  vital  process,  caused  by  the  un- 
causethedue  equal  distribution  of  fluid  in  the  body  in  consequence 

distribution    •     f  .  .   J  .        ?. 

of  the  fluids  of  evaporation,  are  best  seen  m  animals  which  live  in 
water,  in  whom,  therefore,  the  above  explained  cause 
of  motion  in  the  normal  state  does  not  act.  When  a 
fish  is  held  immersed  in  water,  so  that  the  head  is  out 
of  the  water,  while  the  rest  of  the  body  is  covered, 
it  dies  in  a  few  minutes.  It  dies  exactly  in  the  same 
way  when  head  and  gills  are  held  in  the  water,  and 
the  body  in  air  (Milne  Edwards)  ;  in  both  cases,  with- 
out loss  of  weight.  This  fact  shows  that  even  if  the 
weight  of  the  animal  be  kept  unaltered  by  the  absorp- 
tion of  water  through  the  body  kept  in  that  medium, 
yet  the  distribution  of  the  fluids  in  the  body  does  not 
take  place  in  the  proportion  necessary  for  the  preserva- 
tion of  their  vital  functions.  The  fish  dies. 

Experiments       It  is  hardly  necessary  to  remind  the  reader,  that  the 

by  Hales  on  m  J  t           \ 

the  motion  of  experiments  described  in  the   foregoing  pases,  in  so 

the  sap  in 

plants.  far  as  they  permit  us  to  draw  conclusions  as  to  the 
cause  of  the  motion  of  the  juices  of  the  animal  body, 
agree  in  all  respects  with  the  observations  made  on 
plants  by  Stephen  Hales  more  than  120  years  since. 

The  experiments  of  Hales  on  the  mechanism  of  the 
motion  of  the  sap  may  stand  as  a  pattern  to  all  times 
of  an  excellent  method.  That  they  remain,  to  this 
moment,  unsurpassed  in  the  domain  of  vegetable  phys- 
iology, may  be  perhaps  explained  by  the  fact  that 


MOTION    OF    THE    SAP    IN    PLANTS.  191 

they  date  from  the  age  of  Newton.     They  ought  to 
be  familiar  to  every  vegetable  physiologist. 

In  the  beginning  of  his  work,  Hales  describes  the 
experiments  which  he  made  on  the  motion  of  the  sap 
in  plants  in  consequence  of  their  evaporation  in  branch- 
es covered  with  foliage,  in  cut  plants  as  well  as  in 
those  still  provided  with  roots. 

He  shows  by  the  following  experiment  the  influence  influence  of 
of  the  mechanical  pressure  of  a  column  of  water,  with  of  a  column 

,>  •  °f  water, 

and  without  the  help  of  evaporation.  with  and 

.-T,  t       n  i         •          •  •  i   without  the 

To  a  branch  of  an  apple-tree  bearing  its  twigs  and  heipofevap- 
leaves,  Hales  fastened,  air-tight,  a  tube   7  feet  long. 
He   kept  the   branch   with    its   twigs  and   leaves   im- 
mersed in  a  large  vessel  of  water,  and  filled  the  tube 
with  water.     By  the  pressure  of  the  column  of  water,     . 
water  was  forced  into  the  branch,   and  in  2  days  the 
water  in  the  tube  had  sunk  14£  inches. 

On  the  third  day,  he  took  the  branch  out  of  the 
water,  and  exposed  it  to  free  evaporation  in  the  air. 
The  water  in  the  tube  fell,  in  12  hours,  27  inches. 

To  compare  the  force  with  which  water  is  driven 
through  the  vessels  of  the  wood,  by  pressure  alone,  with 
that  produced  by  pressure  and  evaporation,  he  joined 
an  apple  branch,  6  feet  long,  with  leaves,  and  exposed 
to  the  air,  with  a  tube  9  feet  long,  which  was  filled 
with  water. 

From  the  pressure  caused  by  the  column  of  water, 
and  by  the  evaporation  going  on  at  the  surface  of  the 
twigs  and  leaves,  the  water  fell  (Xlth  experiment), 
in  one  hour,  36  inches.  He  now  cut  off  the  branch 
13  inches  below  the  tube,  and  placed  the  portion  cut 
off  (with  the  twigs  and  leaves)  vertically  in  a  vessel 
of  water.  This  last  absorbed,  in  30  hours,  18  ounces 
of  water,  while  the  portion  of  wood  remaining  in  con- 
nection with  the  tube,  which  was  13  inches  long,  only 


192        EXPERIMENTS  OF  HALES  ON  THE 

allowed   6   ounces  of  water   to    pass,  and   that    under 
the  pressure  of  a  column  of  7  feet  of  water. 
Demotion        Hales  shows,  in  three  other  experiments,  that  the 

ol  the  fluids 

caused  by  the  capillary  vessels  of  a  plant,  alone,  and  in  connection 

evaporating          ... 

surface  alone,  with  the  uninjured  roots,  are  easily  filled  with  water 
by  capillary  attraction,  without,  however,  possessing 
the  power  of  causing  the  sap  to  flow  out  and  to  rise 
in  a  tube  attached.  The  motion  of  the  sap,  concludes 
Hales,  belongs  to  the  evaporating  surface  alone ;  he 
proves  that  it  goes  on  in  an  unequal  degree  from  the 
stem,  the  twigs,  the  flowers,  and  fruit,  and  that  the 
effect  of  the  evaporation  stands  in  a  fixed  ratio  to  the 
temperature  and  hygrometric  state  of  the  air.  If  the 
air  were  moist,  but  little  was  absorbed ;  the  absorption 
was  hardly  perceptible  on  rainy  days. 

He  opens  the  second  chapter  of  his  Statistics  with 
the  following  introduction  :  — 

"  Having  in  the  first  chapter  seen  many  proofs  of 
the  great  quantities  of  liquor  imbibed  and  perspired 
by  vegetables,  I  propose  in  this,  to  inquire  with  what 
force  they  do  imbibe  moisture.  Though  vegetables 
(which  are  inanimate)  have  not  an  engine,  which,  by 
its  alternate  dilations  and  contractions,  does  in  animals 
forcibly  drive  the  blood  through  the  arteries  and  veins ; 
yet  has  nature  wonderfully  contrived  other  means,  most 
powerfully  to  raise  and  keep  in  motion  the  sap." 

The  force  Jn  his  experiment  XXL,  he  exposed  one  of  the  chief 

with  which 

sap  is  moved  roots  of  a  pear-tree   in  full  growth  at  a  depth  of  24- 

in  plants 

feet,  cut  off  the  point  of  it,  and  connected  the  part  of 
the  root  left  in  connection  with  the  stem  with  a  tube, 
which  he  filled  with  water,  and  closed  with  mercury. 

In  consequence  of  the  evaporation  from  the  surface 
of  the  tree,  the  root  absorbed  the  water  in  the  tube 
with  such  a  force,  that  in  six  minutes  the  mercury 
rose  to  8  inches  in  the  tube.  This  corresponds  to  a 
column  of  water  9  feet  high. 


MOTION    OF    THE    SAP    IN    PLANTS.  193 

This  force   is  nearly  equal  to  that  with  which  the 
blood  moves  in  the  great  femoral  artery  of  the  horse,  and  blood  iu 
Hales,  in  his  experiment  XXXVI.,  found  the  force  of  ar 
the  blood  in  various  animals  :  —  "  By  tying  those  sev- 
eral animals   down  alive  upon  their  backs,  and    then 
laying  open  the  great  left  crural  artery,  where  it  first 
enters  the  thigh,  I  fixed  to  it  (by  means  of  two  brass 
pipes  which  run  one  into  the  other)   a  glass  tube  of 
above  10  feet  long,  and  ^-th  of  an  inch  in  diameter 
in  bore.     In  which  tube  the  blood  of  one   horse  rose 

8  feet  3  inches,  and  the  blood  of  another  horse  8  feet 

9  inches.     The  blood  of  a  little  dog,  6£  feet  high." 
Hales  showed,  by  special  experiments,  that  the  ab- 
sorbent force  which  he  pointed  out  in  the  root  is  found 
also  in  the  stem,  in  each  separate  twig,  each  leaf,  and 
every  part  of  the  surface ;  and  that  the  motion  of  the 
sap   continues  from  the    root    towards  the   twigs   and 
leaves,  even  when  the  stem  has  been  entirely  stripped 
of  bark,  inner  and  outer.     This   force  acts  not  only 
from  the  roots  in  the.  direction  of  the  summit,  but  also 
from  the  summit  in  the  direction  of  the  root. 

From  his  experiments  he  deduces  the  presence  of 
a  powerful  attractive  force,  residing  in  every  part  of 
the  plant. 

We  now   know,  that  this  attractive  force,  as  such,  This  force  is 

,.,  .  .  atmospheric 

did  not  cause  the  rise  of  the  mercury  or  water  in  his  pressure, 
tubes,  and  it  appears  clearly  from  his  experiments, 
that  the  absorbent  power  of  plants,  of  each  leaf,  of 
each  fibre  of  the  root,  is  sustained  by  a  powerful  ex- 
ternal force,  which  is  nothing  else  than  the  pressure 
of  the  atmosphere. 

By  the  evaporation  of  water  at  the  surface  of  plants,  A  partial 

•  !•       i  .  „  vacuum  is 

a  vacuum  arises  within  them,  in  consequence  of  which  caused  wii^i- 
water  and  matters  soluble  in  water  are  driven  inwards  evaporation. 
and  raised  from  without  with  facility,  and  this  external 
17 


194       EXPERIMENTS  OF  HALES  ON  THE 

pressure,  along  with  capillary  attraction,  is    the  chief 
cause  of  the  motion  and  distribution  of  the  juices. 

With  respect  to  the  absorbent  power  of  the  surface 
of  the  plant  for  gases,  under  a  certain  external  press- 
ure, his  experiments  offer  the  most  beautiful  evidence. 
Hales  says,  in  his  experiment  XXIL,  —  "  This  height  of 
the  mercury  did  in  some  measure  show  the  force  with 
which  the  sap  was  imbibed,  though  not  near  the  whole 
force  ;  for  while  the  water  was  imbibing,  the  transverse 
cut  of  the  branch  was  covered  with  innumerable  little 
hemispheres  of  air,  and  many  air-bubbles  issued  out 
of  the  sap-vessels,  which  air  did  in  part  fill  the  tube 
e  r,  as  the  water  was  drawn  out  of  it ;  so  that  the  height 
of  the  mercury  could  only  be  proportionable  to  the 
excess  of  the  quantity  of  water  drawn  off  above  the 
quantity  of  air  which  issued  out  of  the  wood.  And  if 
the  quantity  of  air  which  issued  from  the  wood  into 
the  tube  had  been  equal  to  the  quantity  of  water  im- 
bibed, then  the  mercury  would  not  rise  at  all ;  because 
there  would  be  no  room  for  it  in  the  tube.  But  if 
9  parts  in  12  of  the  water  be  imbibed  by  the  branch, 
and  in  the  mean  time  but  three  such  parts  of  air  issue 
into  the  tube,  then  the  mercury  must  needs  rise  near 
6  inches,  and  so  proportionably  in  different  cases." 
injury  of  When,  in  his  experiments,  the  root,  the  stem,  or  a 

plants  les«  .    .          ,  ,         -.  •  /Y» 

sens  the         twig  had  been  injured  at  any  part,  by  the  cutting  on 
power.en        of  buds,  root-fibres,  or  small  twigs,  the  absorbent  pow- 
er of  the  remainder  was  diminished  in  a  very  obvious 
degree  (because,  from  these  places,  by  the  entrance 
of  air  the  difference  of  pressure  was  more  easily  equal- 
ized) ;  the  absorbent  power  was    greatest  on  freshly- 
cut   surfaces,    on    which,    however,    it    gradually    de- 
creased, till,  after  several  days,  it  was  not  greater  in 
these  places  than  in  the  uninjured  surface  of  the  plant. 
The  evaporation,  further  argues  Hales,  is  the  power- 


ABSORBENT  POWER  OF  PLANTS.         195 

ful   cause  which  provides  food  for  the  plant  and   its  Evaporation 
vicinity.     Disease  and  death  of  the  plant  follow,  when  to  the  plant. 
the  proportion  between  evaporation  and  supply  is  in- 
terrupted or  destroyed  in  any  way. 

When,  in  hot  summers,  the  earth  cannot  supply, 
through  the  roots,  the  moisture  which  during  the  day 
has  evaporated  through  the  leaves  and  surface  of  the 
tree,  when  the  tree,  or  a  twig  of  it,  dries  up,  the 
motion  of  the  sap  is  arrested  at  these  points.  When 
once  dried,  capillary  action  alone  cannot  restore  the 
original  activity ;  the  evaporation  is  the  chief  con- 
dition of  the  life  of  plants ;  by  its  means  a  permanent 
motion,  a  continually  repeated  change  in  the  quality 
of  the  juice  (sap),  is  effected. 

"  By  comparing,"  says  Hales,  "  the  surface  of  the  Necessity  of. 

J  „  /  .          cutting  off 

roots  of  plants  with    the    surface   of  the    same    plant  branches 

,  .        /.         •         /v  fr°m  a  trans- 

above  ground,  we  see  the  necessity  of  cutting  on  many  planted  tree. 

branches  from  a  transplanted  tree :  for  if  256  square 
inches  of  root  in  surface  were  necessary  to  maintain 
this  cabbage  in  a  healthy  natural  state,  suppose,  upon 
digging  it  up,  in  order  to  transplant,  half  the  roots  be 
cut  off  (which  is  the  case  of  most  young  transplanted 
trees),  then  it  's  plain  that  but  half  the  usual  nourish- 
ment can  be  carried  up,  through  the  roots,  on  that  ac- 
count ;  and  a  very  much  less  proportion,  on  account  of 
the  small  hemisphere  of  earth  the  new-planted  short- 
ened roots  occupy ;  and  on  account  of  the  loose  position 
of  the  new-turned  earth,  which  touches  the  roots  at 
first  but  in  few  points." 

Hales  proves  the  influence   of  suppressed  evapora- 
tion by  the  following  observations  on  hop-vines. 

uNow  there  being  1,000  hills  in  an  acre  of  hop-  Observations 
ground,  and  each  hill  having  three  poles,  and  each  pole  the  blight  in 
three  vines,  the  number  of  vines  will  be  9,000  ;  each 
of  which   imbibing   four  ounces,   the  sum  of  all  the 


196  OBSERVATIONS    OF    HALES    ON 

ounces  imbibed  in  an  acre  in  a  twelve  hours'  day  will 
be  36,000  ounces  =  15,750,000  grains  =  62,007  cubic 
inches,  or  220  gallons;  which  divided  by  6,272,640, 
the  number  of  square  inches  in  an  acre,  it  will  be 
found  that  the  quantity  of  liquor  perspired  by  all  the 
hop-vines  will  be  equal  to  an  area  of  liquor  as  broad 
as  an  acre,  and  T^T  part  of  an  inch  deep,  besides  what 
evaporated  from  the  earth.  And  this  quantity  of  moist- 
ure in  a  kindly  state  of  the  air  is  daily  carried  off  in 
a  sufficient  quantity  to  keep  the  hops  in  a  healthy  state  ; 
but  in  a  rainy,  moist  state  of  air,  without  a  due  mix- 
ture of  dry  weather,  too  much  moisture  hovers  about 
the  hops,  so  as  to  hinder  in  a  good  measure  the  kindly 
perspiration  of  the  leaves,  whereby  the  stagnating  sap 
corrupts,  and  breeds  mouldy  fen,  which  often  spoils  vast 
quantities  of  flourishing  hop-grounds. 

"  This  was  the  case  in  the  year  1723,  when  ten  or 
fourteen  days'  almost  continual  rains  fell,  about  the  lat- 
ter half  of  July,  after  four  months'  dry  weather  ;  upon 
which  the  most  flourishing  and  promising  hops  were  all 
infected  with  mould  or  fen,  in  their  leaves  and  fruit, 
whilst  the  then  poor  and  unpromising  hops  escaped, 
and  produced  plenty  ;  because  they,  being  small,  did 
not  perspire  so  great  a  quantity  as  the  others  ;  nor  did 
they  confine  the  perspired  vapor,  so  much  as  the  large 
thriving  vines  did,  in  their  shady  thickets.  This  rain 
on  the  then  warm  earth  made  the  grass  shoot  out  as 
fast  as  if  it  were  in  a  hot-bed  ;  and  the  apples  grew  so 
precipitately,  that  they  were  of  a  very  fleshy  constitu- 
tion, so  as  to  rot  more  remarkably  than  had  ever  been 
remembered. 

"The  planters  observe,  that,  when  a  mould  or  fen  has 
once  seized  any  part  of  the  ground,  it  soon  runs  over 
the  whole  ;  and  that  the  grass,  and  other  herbs  under 
the  hops,  are  infected  with  it. 


THE    BLIGHT   IN    HOPS.  197 

"  Probably  because  the  small  seeds  of  this  quick- 
growing  mould,  which  soon  come  to  maturity,  are 
blown  over  the  whole  ground  Which  spreading  of 
the  seed  may  be  the  reason  why  some  grounds  are  in- 
fected with  fen  for  several  years  successively." 

"I  have  in  July  (the  season  for  fire-blasts,  as  the  Fire-blasts  in 

hops. 

planters  call  them)  seen,"  says  Hales,  "  the  vines  in 
the  middle  of  a  hop-ground  all  scorched  up,  almost 
from  one  end  of  a  large  ground  to  the  other,  when  a 
hot  gleam  of  sunshine  has  come  immediately  after  a 
shower  of  rain  ;  at  which  time  the  vapors  are  often 
seen  with  the  naked  eye,  but  especially  with  reflecting 
telescopes,  to  ascend  so  plentifully,  as  to  make  a  clear 
and  distinct  object  become  immediately  very  -dim  and 
tremulous.  Nor  was  there  any  dry,  gravelly  vein  in 
the  ground,  along  the  course  of  this  scorch.  It  was 
therefore,  probably  owing  to  the  much  greater  quantity 
of  scorching  vapors  in  the  middle  than  outsides  of  the 
ground,  and  that  being  a  denser  medium,  it  was  much 
hotter  than  a  more  rare  medium. 

"  This  is  an  effect  which  the  gardeners  about  Lon- 
don have  too  often  found  to  their  cost,  when  they  have 
incautiously  put  bell-glasses  over  their  cauliflowers 
early  in  a  frosty  morning,  before  the  dew  was  evapo- 
rated off  them  ;  which  dew  being  raised  by  the  sun's 
warmth,  and  confined  within  the  glass,  did  there  form 
a  dense,  transparent,  scalding  vapor,  which  burnt  and 
killed  the  plants." 

When  these  observations  are  translated  into  our  pres- 
ent language,  we  perceive  with  what  acuteness  and  ac- 
curacy Hales  recognized  the  influence  of  evaporation  Hales  recog- 

xi_      T/»       f      i  nized  the  in- 

on  the  hie  ol  plants.  •  nuenceof 

According  to  him,  the  development  and  growth  of  ^tSulfe" 
the  plant  depends  on  the  supply  of  nourishment  and  of  plar 
moisture  from  the  soil,  which  is  determined  by  a  cer- 
17* 


198 


ORIGIN    OF    THE    POTATO    BLIGHT. 


Decaying 
juices  of 
plants  be- 
come a  fe  I'- 
ll le  soil  for 
microscopic 
plants. 


Origin  of  the 
potato  dis- 
ease is  prob- 
ably similar 
to  that  of  the 
blight  in 
hops. 


The  potato 
disease  long 
known. 


tain  temperature  and  dryness  of  the  atmosphere.  The 
absorbent  power  of  plants,  the  motion  of  their  sap, 
depends  on  evaporation  ;  the  amount  of  food  neces- 
sary for  their  nutrition,  which  is  absorbed,  is  propor- 
tional to  the  amount  of  moisture  given  out  (evaporated) 
in  a  given  time.  When  the  plant  has  taken  up  a  max- 
imum of  moisture,  and  the  evaporation  is  suppressed 
by  a  low  temperature  or  by  continued  wet  weather,  the 
supply  of  food,  the  nutrition  of  the  plant,  ceases  ;  the 
juices  stagnate,  and  are  altered  ;  they  now  pass  into  a 
state  in  which  they  become  a  fertile  soil  for  microscopic 
plants.  When  rain  falls  after  hot  weather,  and  is  fol- 
lowed by  great  heat  without  wind,  so  that  every  part  of 
the  plant  is  surrounded  by  an  -  atmosphere  saturated 
with  moisture,  the  cooling  due  to  further  evaporation 
ceases,  and  the  plants  are  destroyed  by  fire-blast  or 
scorching  (Sonnenbrand,  German,  literally  sun-lurn  or 
sun-blight). 

After  the  experience  and  observations  of  so  long  a 
period  in  reference  to  the  influence  of  evaporation  on 
the  condition  of  plants,  I  hardly  think  that  any  unprej- 
udiced observer  can  entertain  the  smallest  doubt  con- 
cerning the  cause  of  the  great  mischief  which  has  be- 
fallen agriculture  during  the  last  few  years.  If  Hales, 
that  unequalled  observer  and  inquirer,  had  known  the 
potato  disease,  I  hardly  believe  that  he  would  have  as- 
cribed it  to  an  internal  cause  belonging  to  the  plant, 
any  more  than  he  thought  of  ascribing  the  blight  of 
the  hop-plants,  formerly  mentioned,  to  a  special  hop 
disease,  or  the  rotting  of  the  apples  to  an  apple  disease. 
Even  Parmentier,  to  whom  France  is  indebted  for  the 
introduction  of  the  potato,  knew  this  disease,  and  has 
very  accurately  described  it.  The  term  "  potato-rot  " 
has  been  known  to  the  oldest  peasants  and  agricul- 
turists since  their  youth  ;  it  has,  doubtless,  only  acquired 


ORIGIN    OF    THE    POTATO    BLIGHT.  199 

of  late  years  the  frightful  significance,  which  seems  to 
threaten  the  well-being  of  nations,  since  the  causes, 
which  formerly  brought  it  locally  into  existence,  have 
spread  over  whole  districts  and  countries.  The  writ- 
ings of  Hales  bring  to  our  century  from  a  preceding 
one  the  consoling  certainty  (and  this  is  especially  im- 
portant), that  the  cause  of  this  decay  is  not  to  be  its  great 

.  .  prevalence  in 

looked  for  in  a  degeneration  of  the  plant,  but  depends  the  last  few 
on  the  combination  of  certain  conditions  accidentally  pends  on  the 

.  ,  til  combination 

coincident ;  and  that  these,  when  they  are  well  ascertain-  of  certain 

i          ,    ,  .  conditions 

ed  and  kept  in  view,  enable  the  agriculturist,  if  not  to  accidentally 
annihilate,  at  least  to  diminish,  their  hurtful  influence,      and  not  on 

The  potato-plant  obviously  belongs  to  the  same  class  tioen  of^e* 
of  plants  as  the  hop-plant ;  namely,  to  that  class  which  species*8 ' 
is  most  seriously  injured  by  the  stagnation  of  their 
juices  in  consequence  of  suppressed  transpiration.  Ac- 
cording to  Knight,  the  tubers  are  not  formed  by  swell- 
ing of  the  proper  roots,  but  by  the  development  of  a 
kind  of  underground  stalks  or  runners.  He  found  that 
when  the  tubers  under  ground  were  suppressed,  tubers 
were  formed  on  the  stalks  above  ground  ;  and  it  is  con- 
ceivable that  every  external  cause  which  exerts  a  hurt- 
ful influence  on  the  healthy  condition  of  the  leaves  and 
stalks  must  act  in  like  manner  on  the  tubers.  In  the 
districts  which  were  most  severely  visited  by  the  so- 
called  potato  disease  in  1846,  damp,  cold,  rainy  weath- 
er followed  a  series  of  very  hot  days  ;  and  in  1847, 
cold  and  rain  came  on,  after  continued  drought,  in  the 
beginning  of  September,  exactly  at  the  period  of  the 
most  luxuriant  growth  of  the  potatoes. 

In  most  places,  no  trace  of  disease  was  observed  in 
the  early  potatoes  before  the  middle  of  August ;  and 
even  after  that  period,  low-lying,  cold,  and  wet  fields 
were  chiefly  attacked  by  it.  In  many  plants,  in  the 
same  field  in  which  the  seed  potatoes  had  been  de- 


200  EFFECT    OF    COLD    ON    PLANTS. 

stroyed  by  putrefraction  and  decay,  the  tubers  appeared 
quite  healthy,  while  in  others  it  was  easy  to  see  that 
those  tubers  alone  which  lay  next  to  the  old  potatoes 
were  infected  and  attacked  by  the  disease,  and  that  on 
the  side  next  to  the  old  tubers. 

observations       In  1846  all  the  potato-plants  in  my  garden  died  com- 

thor.  pletely  off  towards  the  end  of  August,  before  a  single 

tuber  had   been  formed  ;    and  in    1847,  in  the  same 

field,  the  tubers  of  all  those  plants  which  stood  under 

trees  and  in  protected  spots  were  quite  rotten,  while  no 

trace  of  disease  appeared  in  spots  which  were  more 

elevated  and  more  fully  exposed  to  the  current  of  air. 

The  cause  is  The  cause  of  the  disease  is  the  same  which,  in  spring 

the  same  as  .     _  -     .         .  .. 

that  which  and  autumn,  excites  influenza  ;  *  that  is,  the  disease  is 
enza.es '  u"  the  effect  of  the  temperature  and  hygrometric  state  of 
the  atmosphere,  by  which,  in  consequence  of  the  dis- 
turbance of  the  normal  transpiration,  a  check  is  sud- 
denly, or  fbr  a  considerable  time,  given  to  the  motion 
of  the  fluids,  which  is  one  chief  condition  of  life,  and 
which  thus  becomes  insufficient  for  the  purposes  of 
health,  or  even  hurtful  to  the  individual. 

The  whole  existence  of  a  plant,  the  resistance  which 
it  opposes  to  the  action  of  the  atmospheric  oxygen,  is 
most  closely  connected  with  the  continued  support  of 
its  vital  functions.  The  mere  alternation  of  day  and 
night  makes,  in  this  respect,  a  great  difference.  The 
sinking  of  the  external  temperature  by  a  few  degrees 
causes  the  leaves  to  fall  in  autumn  ;  and  a  cold  night  is 
followed  by  the  death  of  many  annual  plants. 

*  Schonbein  has  observed  that  the  prevalence  of  influenza 
and  the  presence  of  ozone  in  the  air  are  in  proportion  to  each 
other.  Is  it  yet  to  be  found  that  there  are  causes  influencing  the 
quantity  of  this  form  of  oxygen  in  the  air,  —  causes  more  ener- 
getic in  the  last  few  years  than  hitherto  ?  The  circumstance, 
that  ozone  greatly  hastens  decay,  adds  interest  to  the  inquiry. — 
E.  N.  H. 


CONDITIONS    OF    THE    LIFE    OF    PLANTS.  201 

If  we  reflect  that  a  plant,  in  order  to  protect  itself 
from  external  causes  of  disturbance,  or  to  seek  the 
food  which  it  requires,  cannot  change  its  place  ;  that 
its  normal  vital  functions  depend  on  the  simultaneous 
and  combined  action  of  water,  of  the  soil,  of  the  ex- 
ternal temperature,  and  of  the  hygrometric  state  of  the 
atmosphere  ;  that  is,  on  four  external  circumstances  ;  The  life  of 

•     •  i         11         !•         i  />  />          •  plants  is  de- 

it  is  easy  to  comprehend  the  disturbance  of  functions  pendent 

which  must  occur  in  the  organism  in  consequence  of  four  exter- 
any  change  in  the  mutual  relations  of  so  many  com- 
bined agencies.  The  state  of  a  plant  is  a  sure  indi- 
cation of  equilibrium  or  of  misproportion  in  the  exter- 
nal conditions  of  its  life  ;  and  the  dexterity  of  the  ac- 
complished gardener  consists  exactly  in  this,  that  he 
knows  and  can  establish  the  just  proportion  of  these 
conditions  for  each  species  of  vegetable.  Only  one  of 
these  numerous  conditions  is  in  the  power  c^the  agri- 
culturist, and  that  is,  the  production  of  the  quality  of 
the  soil  appropriate  for  the  crop,  including  the  necessa- 
ry modification  of  its  composition,  by  the  mechanical 
working  of  the  soil ;  by  the  irrigation  or  draining  of  his 
fields ;  and  lastly,  by  the  employment  of  manure. 
When  one  of  the  constituents  of  the  soil,  which,  under  only  one  of 

...  .  -         ,  which,  name- 

the  given  circumstances,  is  necessary  for  the  support  iy,  the  quai- 
of  the  vital  functions,  is  absent,  the  external  injurious  soiijsVthe 
influence  is  strengthened  by  this  deficiency.     Had  this  agriculturist6 
constituent  been  present,  the  plant  would  have  been 
enabled  to  oppose  to  the  external  hurtful  influences  a 
continued  resistance.     One  day  may  be  decisive  as  to 
the  life  or  death  of  a  plant.     An  accurate  knowledge 
of  the  influence  exerted  by  the  various  constituents  of 
the  soil  on  the  diseased  condition  must  enable  the  ag- 
riculturist to  protect  and  preserve  many  of  his  fields 
for  a  long  time  from  this  destruction  ;  but  it  is  obvi- 
ous that  a  universal  remedy  against  this  evil  does  not 
exist. 


202  RISE    OF    THE    SPRING    SAP. 

Effects  of  When  the  vessels  of  the  plant  are  filled  to  overflow- 

suppressed      ... 
evaporation,    ing  with  water,  and  the  motion  of  the  sap  is  suppressed, 

the  nutrition,  in  most  plants,  is  arrested,  and  death 
takes  place.  Every  one  knows  the  effect  of  a  sudden 
or  of  a  gradual  overfilling  of  certain  parts  or  organs, 
when  the  corresponding  evaporation  is  suppressed.  By 
the  endosmotic  pressure  of  the  water  flowing  towards 
those  cells  which  contain  sugar,  mucilage,  gum,  albu- 
men, and  soluble  matters  in  general,  the  juicy  fruits 
and  seeds  approaching  maturity  burst,  and  the  juice  of 
grapes,  cherries,  plums,  &e.,  passes,  on  contact  with 
the  air,  into  a  state  of  progressive  change.  The  fungi 
which  have  been  observed  on  the  potato-plants,  and 
the  putrefaction  of  the  tubers,  are  not  the  signs  of 
a  disease,  but  the  consequences  of  the  death  of  the 
plant. 

of^HaiSon3       Amono^he  most  important  of  the  experiments  made 
the  rise  of      by  Hales,  we  must  reckon  undoubtedly  those  on  the 

spring  sap  in     /  7 

perennial  rise  of  the  spring  sap  in  perennial  plants.  His  obser- 
vations have  been  entirely  confirmed  by  all  those  who 
since  his  time  have  studied  the  subject ;  but,  in  my 
opinion,  without  our  having  approached  one  step  nearer 
to  the  cause  of  the  phenomena. 

The  most  recent  experiments  on  this  subject  by  E. 
Briicke,  leave  no  doubt  in  regard  to  the  actual  state  of 
our  knowledge. 

Dutrochet  According  to  Dutrochet,  it  is  the  extremities  of  the 
radical  fibres,  called  by  De  Candolle  spongioles,  which 
effect  the  rise  of  the  spring  sap ;  and  he  believes 
(L' Agent  Immediat  du  Mouvement  Vital,  Paris,  1826) 
that  the  force  with  which  the  sap  is  driven  upwards 
acts  from  the  root.  Dutrochet  cut  off  a  piece  of  a  vine- 
stem,  two  metres  long ;  and  he  saw  that  the  sap  flowed 
steadily  from  the  shortened  stem  in  connection  with  the 
root.  When  he  had  again  cut  it  off  close  to  the 


THEORY    OF    DUTROCHET.  203 

ground,  he  observed  that  the  portion  in  the  ground  con- 
tinued to  pour  forth  sap  from  the  whole  cut  surface. 
He  pursued  the  experiment,  going  deeper  every  time, 
and  he  always  found  that  the  sap  flowed  from  the  part 
left  in  the  ground,  till  at  last  he  came  "to  the  extreme 
points  of  the  fibres,  in  which  he  then  located  the  origin 
of  the  moving  force. 

The  peculiar  activity  of  the  spongioles  must,  accord- 
ing to  Dutrochet,  be  ascribed  to  all  the  causes,  taken 
together,  which  determine  the  phenomena  of  Endos- 
mosis. 

Now  that  we  are  better  acquainted  with  the  phenom-  objections  to 
ena  of  what  is  called  Endosmosis,  we  may  oppose  ofloutrlShet. 
to  this  view  some  well-founded  doubts.  All  observers 
agree,  that  the  increase  in  volume  of  a  liquid,  separat- 
ed from  another  liquid  by  a  porous  diaphragm,  is  de- 
termined by  a  difference  in  the  qualities  of  the  two 
liquids.  If  their  composition  and  properties  be  the 
same,  there  is  no  cause  sufficient  to  produce  mixture 
and  change  of  volume,  since  in  this  case  the  attrac- 
tion of  both  for  the  diaphragm  and  for  each  other  is 
perfectly  equal. 

In  the  course  of  his  admirable  researches,  Briicke  Observation 

t.,of  Briicke  on 

determined  the  specific  gravity  of  the  spring  sap  which  the  specific 
had  flowed  from  the  vine.     He  found  it,  in  one  plant,  spring7 sap  in 
=  1.0008,  and  in  another,  =  1.0009.* 

These  numbers  prove  irresistibly,  that  the  specific 
gravity  of  the  sap  of  the  vine  is  in  no  way  different 
from  that  of  ordinary  spring  water,  or  of  the  water 
which  has  filtered  through  garden  mould.  In  most 
cases,  spring  water  contains  even  more  dissolved  matter. 

The  spring  sap  of  the  vine  which  had  the  sp.  g. 
1.0008  raised  a  column  of  mercury  to  the  height  of 
174  lines  (14.5  inche's),  and  therefore  exerted  a  press- 

*  Poggendorfs  Annalen  der  Physik,  LXIII.  177. 


204  RISE    OF    THE    SPRING    SAP. 

ure  equal  to  that  of  a  column  of  water  195  inches 
high.  It  is  quite  impossible  to  account  for  this  pressure 
by  the  difference  in  the  amount  of  dissolved  matter 
in  the  water  absorbed  by  the  roots,  and  the  sap  flowing 
from  the  cut  surface.  In  the  experiment  No.  IX.  of 
Briicke,  made  with  a  vine  the  sap  of  which  had  the 
sp.  g.  1.0009,  the  mercury  was  raised  at  7  A.  M.  to  the 
height  of  209  lines  (nearly  17.5  inches). 

No  one  can  doubt  that  what  is  called  Endosmosis  has 
some  share  in  the  rise  of  the  sap  of  the  maple  and 
birch  trees,  which  is  proportionally  rich  in  sugar,  and 
differs  materially  in  composition  from  spring  water,  as 
well  as  on  the  flow  or  exudation  of  gummy  or  saccha- 
rine juices ;.  but  the  pressure  exerted  in  these  cases 
cannot  be  compared  to  that  exerted  by  the  sap  of  the 
vine,  where  the  causes  included  under  the  word  Endos- 
mosis cannot  act. 
The  cause  of  It  is  evident,  that  the  cause  of  the  pressure  of  the 

the  rise  of  .  .  .  . 

the  spring  spring  sap  must  be  transient,  called  into  action  by  ex- 
transient,  ternal  causes,  and  limited  to  a  short  period.  The  ex- 
periment of  Dutrochet,  from  which  he  concludes  that  the 
cause  of  the  rise  of  the  sap  resides  in  the  extreme 
points  of  the  roots,  may  be  thus  interpreted  :  —  "  The 
cause  of  the  efflux  and  pressure  of  the  sap  exists  in 
all  parts  of  the  uninjured  plant,  down  to  the  extreme 
spongioles  of  the  root." 

The  present  season  does  not  admit  of  experiments 
on   this   point;  but   as   spring  approaches,   it  may  be 
proper   here  to   develop   more  clearly  the  grounds  of 
the  opinion,  that  the  cause  of  the  efflux  of  the  sap  of 
the  vine  is  a  transient  one.     Perhaps  some  one  may 
thus  be  induced  to  decide  experimentally  all  the  ques- 
tions connected  with  this  remarkable  phenomenon. 
Experiments       Hales,  in  his  experiment  XXXIV.,  cut  off  a  vine- 
of  Hales.        gtem  ^  feet  aDOVe  the  ground,  and  attached  to  the  trunk 


EXPERIMENTS    OF    HALES.  205 

tubes  of  7  feet  long,  joined  together.  Below  the  cut 
there  were  no  branches.  This  was  done  on  the  30th 
of  March,  at  3  p.  M. 

As  the  stem  poured  out  no  sap  on  that  day,  he  poured 
water  into  the  attached  tube  to  the  height  of  two  feet. 

This  water  was  absorbed  by  the  stem,  so  that  at  about 
8  P.  M.  the  water  had  fallen  to  3  inches  in  the  tube. 

The  next  day,  at  ^  past  6  A.  M.,  the  sap  stood  three 
inches  higher  than  at  8  the  evening  before.  From  this 
time  the  sap  continued  to  rise,  till  it  reached  a  height  of 
21  feet.  It  would  perhaps,  says  Hales,  have  risen  high- 
er, had  the  joinings  of  the  tubes  been  more  water  tight. 

Whatever  opinion  we  rnay  entertain  as  to  the  cause  The  cause 

n     ,          m  „    ,  ...  ..  ,      of  the  motion 

of  the  efflux  and  pressure  of  the  sap,  it  is  impossible  of  the  sap 

.        .      ,  exists  not 

to  suppose  that  the  mechanical  or  any  other  structure  merely  in  the 
or  quality  of  the  radical  fibres,  the  spongioles,  or  the  SJun1^!?' 
inner   parts    of    the    vine-stem    generally,   can    have  pfant.0 
changed  so  much  between  the  evening  of  the  30th  and 
the  morning  of  the  31st  as  to  give  rise  to  two  com- 
pletely opposite  influences. 

On  the  evening  of  the  30th,  the  water  poured  into 
the  tube  was  absorbed ;  on  the  31st,  it  was  expelled 
with  a  continually  increasing  force. 

In  his  experiment  XXXVII.,  Hales  fixed,  on  three 
branches  of  a  horizontally  trained  espalier  vine,  siphon 
tubes,  filled  to  a  certain  point  with  mercury. 

The  three  branches  received  their  sap  from  the  com- 
mon stem,  that  stem  from  the  root.  The  first  branch 
was  7  feet  from  the  second,  the  second  22  feet  8  inches 
from  the  third.  The  first  and  third  branches  were  two 
years  old,  the  middle  one  was  older. 

From  the   4th   to   the   20th  of  April,  the   mercury 
stood,  in  consequence  of  the  pressure  of  the  sap,  high- 
er in  the  open  limb  of  the  tubes  than  in  the  other,  which 
was  attached  to  the  branch. 
18 


206       CONCLUSIONS  DEDUCED  BY  HALES. 

The  greatest  height  attained  by  the  mercury  was 
from  21  to  26  inches. 

On  the  21st  of  April,  when  the  flowering  was  nearly 
over,  the  sap  in  the  middle  branch  went  backwards ;  it 
was  absorbed,  and  so  considerably,  that  the  mercury 
stood  4  inches  lower  in  the  open  limb  than  in  the  other. 
After  a  rainy  night,  on  the  24th  of  April,  the  sap  again 
rose  in  the  open  tube  4  inches. 

In  the  first  (lowest)  branch,  the  sap  went  back  on  the 
29th  of  April,  9  days  after  the  middle  one ;  the  third 
(highest)  branch  only  began  to  absorb  the  sap  on  the 
3d  of  May,  13  days  after  the  middle  one. 

Conclusions        We  see  from  this  experiment,  as  Hales  observes, — 
Hales.  "  That  the  cause  which  produces  the  flow  of  the  sap 

does  not  proceed  from  the  root  alone,  but  that  it  belongs 
to  a  force  inherent  in  the  stem  and  branches.  For  the 
middle  branch  followed  more  rapidly  the  changes  of 
temperature,  of  dryness  and  of  moisture,  than  the  two 
others,  and  absorbed  the  sap  nine  days  before  one,  and 
thirteen  days  before  the  other,  both  of  which,  during 
this  time,  poured  out  sap  instead  of  absorbing  it.  (The 
cause  of  the  efflux  and  pressure  had,  in  the  older 
branch,  disappeared,  and  given  place  to  an  opposite  in- 
fluence, while  it  still  continued  active  in  the  two  young- 
er branches.) 

"  The  middle  branch  was  3  feet  8  inches  higher  than 

that  next  the  stem.     The  height  of  the  mercury  in  the 

three  tubes  was,  respectively,  14£,  12£,  and  13  inches. 

The    maximum    was   21,   26,  and  26  inches.     These 

numbers  prove  that  the  greater  length  of  the   middle 

branch  had  no  perceptible  influence  on  the  height  of 

the  mercury,  as  compared  with  that  in  the  other  tube." 

Effectsofcoid      In   his    experiment    XXXVIII. ,    Hales   observes, — 

Emotion  of  "  Moisture  and  warmth  made  the  sap  most  vigorous. 

If  the  beginning  or  middle  of  the  bleeding  season,  be- 


CONCLUSIONS  DEDUCED  BY  HALES.        207 

ing  very  kindly,  had  made  the  motion  of  the  sap  vig- 
orous, that  vigor  would  immediately  be  greatly  abated 
by  cold  easterly  winds.* 

"  If  in  the  morning,  while  the  sap  is  in  a  rising  state, 
there  was  a  cold  wind  with  a  mixture  of  sunshine  and 
cloud,  when  the  sun  was  clouded,  the  sap  would  imme- 
diately visibly  subside,  at  the  rate  of  an  inch  in  a  min- 
ute for  several  inches,  if  the  sun  continued  so  long 
clouded ;  but  as  soon  as  the  sunbeams  broke  out 
again,  the  sap  would  immediately  return  to  its  then 
rising  state,  just  as  any  liquor  in  a  thermometer  rises 
and  falls  with  the  alternacies  of  heat  and  cold  ;  whence 
it  is  probable,  that  the  plentiful  rise  of  the  sap  in  the 
vine  in  the  bleeding  season  is  effected  in  the  same 
manner." 

If  we  consider  that  the  sap  in  spring,  even  with  a 
clouded  sky,  does  not  cease  to  rise  and  flow,  for  this 
even  goes  on  during  the  night,  we  cannot  explain  the 
fall  of  the  sap  from  the  moment  that  the  sun  was  cov- 
ered by  a  cloud  by  a  mere  change  of  temperature  in 
the  juice,  because  the  time  was  too  short  for  the  cooling 
and  contraction  by  cooling  (one  inch  in  a  minute). 
Heat  determined  the  more  rapid  rise,  and  cold  the  fall ; 
but  they  acted  on  a  cause  which  lay  higher  than  the 

*  The  influence  of  cold  easterly  winds,  producing  what  is 
called  blight  upon  apple-trees,  is  well  known  about  the  eastern 
extreme  of  Long  Island.  The  explanation  with  the  views  here 
expounded  is  simple.  The  vigorous  development  of  the  tree  de- 
pends upon  the  supply  of  nutriment  from  the  soil.  This  requires 
ascent  of  the  sap.  This  ascent  requires  evaporation  from  the 
leaves.  The  evaporation  depends  upon  the  capacity  of  the  at- 
mosphere to  take  up  moisture.  The  dryer  winds  from  the  west 
will  promote  the  evaporation,  while  those  from  off  the  sea,  laden 
with  moisture  and  protracted  through  several  days,  will  im- 
pede it.  The  shrinking  of  the  leaves,  an  evidence  of  deficient 
nourishment,  follows.  —  E.  N.  H. 


208  THE  ASCENT  OF  THE  SAP  MAY  BE  CAUSED  BY  A  GAS. 

root,  and  which  was  more  sensitive  to  heat  than  the 
liquid  itself. 

Hales  says,  in  his  experiment  XXXVIII.,  —  "  In  very 
hot  weather  many  air-bubbles  would  rise,  so  as  to  make 
a  froth  an  inch  deep  on  the  top  of  the  sap  in  the  tube. 

"  I  fixed  a  small  air-pump  to  the  top  of  a  long  tube, 
which  had  twelve  feet  height  of  sap  in  it ;  when  I 
pumped,  great  plenty  of  bubbles  arose,  though  the  sap 
did  not  rise,  but  fell  a  little,  after  I  had  done  pumping." 

In  his  experiments  on  the  amount  of  air  absorbed  by 
plants,  chapter  V.,  he  observes,  "  in  the  experiments  on 
vines,  the  very  great  quantity  of  air  which  was  contin- 
ually ascending  from  the  vines,  through  the  sap  in  the 
tubes ;  which  manifestly  shows  what  plenty  of  it  is 
taken  in  by  vegetables,  and  is  perspired  off  with  the  sap 
through  the  leaves." 

When  we  take  these  facts  into  consideration,  the 
opinion  appears  not  untenable,  that  the  incomprehensi- 
ble force  which  causes  the  sap  of  the  vine  to  flow  in 
spring  may  be  simply  referred  to  a  disengagement  of 
gas  which  takes  place  in  the  capillary  vessels  (filled 
with  liquid,  and  keeping  themselves  constantly  full),  in 
consequence  of  a  kind  of  germination  ;  and  it  is  possi- 
ble that  the  height  of  the  column  of  mercury,  or  of 
water,  is  only  a  measure  of  the  elasticity  of  the  disen- 
gaged gas. 

Let  us  suppose  a  strong  glass  bottle,  in  the  mouth  of 
which  a  long  tube,  open  at  both  ends,  and  reaching  to 
the  bottom,  is  cemented,  to  be  filled  with  a  liquid  in 
which,  from  any  cause,  a  gas  is  disengaged  (solution  of 
sugar  mixed  with  yeast,  for  example) ;  it  is  evident  that 
the  liquid  must  rise  in  the  tube  from  the  separation  of 
the  gas.  When  it  has  risen  to  32  feet,  the  gas  will 
occupy  only  the  half,  and  at  64  feet,  one  third,  of  its 
volume  under  the  usual  atmospheric  pressure.  In  this 


IS    THIS    GAS    CARBONIC   ACID  ?  209 

case,  the  height  of  the  liquid  in  the  tube  is  no  measure 
of  a  special  power  residing  in  the  walls  of  the  vessel  ; 
it  only  shows  the  tension  of  the  gas. 

If  the  walls  of  the  vessel  were  permeable  to  the  gas, 
under  a  certain  pressure,  no  further  rise,  beyond  that 
point,  could  occur. 

If  in  the  apparatus,  Fig.  4,  we  push  the  tube  a 
through  the  cork  down  to  the  little  lead  drop ;  if  we 
then  fill  the  tube  c  with  water  to  which  some  yeast  has 
been  added,  and  a  with  solution  of  sugar,  and  expose 
the  whole  to  a  temperature  of  from  68°  to  75°,  the 
liquid  rises  in  Z>,  from  the  gas  disengaged  in  c,  very 
rapidly,  so  as  to  overflow.  If  c  be  filled  with  solution 
of  sugar,  and  a  with  yeast,  the  same  rise  occurs,  and 
lasts  till  the  disengaged  gas  puts  an  end  to  the  contact 
between  the  membrane  and  the  liquid. 

It  is  hardly  necessary  to  point  out,  that  the  idea 
above  expressed,  as  to  the  cause  of  the  flow  and  press- 
ure of  the  spring  sap,  is  nothing  more  than  an  indica- 
tion of  the  direction  in  which  experiments  must  be 
made.  When  we  know  with  accuracy  the  volume  of 
the  liquid  which  flows  out  of  a  vine  at  the  time  of 
flowering,  and  the  quantity  of  gas  which  is  developed  Gas  is  proba- 
at  the  same  time,  we  shall,  I  trust,  find  ourselves  a  step 
nearer  to  the  explanation  of  this  phenomenon.  Ac- 
cording to  the  experiments  of  Geiger  and  Proust,  the 
sap  of  the  vine  is  rich  in  carbonic  acid  ;  and  it  is  possi- 
ble that  the  gas  which  is  disengaged  may  be  no  other 
than  carbonic  acid  gas. 


18 ' 


APPENDIX. 


A.  -  (p.  22.) 

THE  suggestion  in  the  editor's  paper  upon  Glycocoll, 
that  organized  bodies  are  composed  of  lesser,  already 
distinctly  formed  groups,  has  met  with  .strong  support  in 
an  elaborate  investigation  by  Dr.  Guckelberger,*  As- 
sistant in  the  Giessen  Laboratory.  M.  Schlieper  had 
studied  with  care  the  products  of  decomposition  of 
gelatine  by  chromic  acid.  Dr.  Guckelberger  treated 
caseine,  albumen,  and  fibrine  both  by  manganese  and 
chromic  acid,  and  found  that,  except  in  relative  quanti- 
ties, the  products  of  decomposition  were  the  same  or 
greatly  alike  in  all. 

Now,  as  Dr.  G.  has  aptly  remarked,  there  being  no 
essential  difference  in  the  nature  of  the  products  yield- 
ed by  the  oxidation  with  manganese  from  those  yielded 
by  oxidation  with  chromic  acid,  notwithstanding  these 
agents  hold  oxygen  with  unequal  degrees  of  affinity,  it 
follows  that  it  is  the  presence  of  oxygen,  not  its  quan- 
tity, that  determines  the  character  of  the  bodies  pro- 
duced. The  oxygen  serves  to  separate  bodies,  already 
formed,  from  each  other's  embrace.  It  removes  a  ce- 
ment that  held  the  members  of  a  structure  together. 

The  following  bodies  were  obtained  by  Dr.  Guckel- 

*  Liebig's  Annalen,  LXIV.  p.  39. 


212  APPENDIX. 

berger  in  the  distillate  from  caseine,  black  oxide    of 
manganese,  and  sulphuric  acid  :  — 

1.  Aldehyde  of  acetic  acid,     .  .  .  C5  H3  O,   HO 

2.  Aldehyde  of  metacetonic  acid,  .  Ce   HS  O,   HO 

3.  Aldehyde  of  butyric  acid,  .  .  .  C5   H3  O,   HO 

4.  Oil  of  bitter  almonds,  .  .  CM  H5  O2,  H 

5.  Formic  acid,  .  .  .  C2   H     O3,  HO 

6.  Acetic  acid,      .  C4   H3  O3,  HO 

7.  Metacetonic  acid,     .  .  .  .  Ce   Hs  O3,  HO 

8.  Butyric  acid,     .  .  .  .  C8   H7  O3,  HO 

9.  Valerianic  acid,        .  .  .  .  Ci0  Hg  O3,  HO 

10.  Caproic  acid,  Ci2  Hu  O3,  HO 

11.  Benzoic  acid,  .  .  .  .  CM  Hg  O3,  HO 

The  following  bodies  were  obtained  on  decomposing 
caseine  with  chromate  of  potash  and  sulphuric  acid  :  — 

1.  Aldehyde  of  metacetonic  acid,       .  .  Ce   H5  O,   HO 

2.  Oil  of  bitter  almonds  (in  small  quantity),  CM  HS  O2,  H 

3.  Formic  acid  (in  small  quantity),     .  .  Cg   H     O3,  HO 

4.  Acetic  acid,      .  .  .  .  C4   H3  O3,  HO 

5.  Butyric  acid,             .             .             .             .  C8  H7  O3,  HO 
6    Valerianic  acid,            .             .            .  Cio  Hg  O3,  HO 

.7.  Benzoic  acid  (with  traces  of  caproic  acid). 

8.  Benzoic  acid,   .  .  .  .  CH  H5  O3,  HO 

9.  Prussic  acid,  .  .  .  .  C2  N     H, 

10.  Valeronitrile,    .  .  .  .  C10  H9  N, 

11.  A  heavy  oil  with  the  odor  of  cinnamon. 

12.  Metacetonic  acid,    .  .  .  .  C6   H5  Os,  HO 

EBEN  N.  HORSFORD. 


APPENDIX.  213 


B. 

ON  THE   NATURE  AND   PREVENTION   OF  THE 
POTATO  DISEASE. 

AFTER  the  preceding  pages  were  in  print,  I  received 
from  Baron  Liebig  a  copy  of  the  Journal  of  the  Agri- 
cultural Association  of  the  Grand  Duchy  of  Hesse 
(Darmstadt),  No.  7,  dated  15th  February,  1848,  contain- 
ing the  account  of  a  method  proposed  by  Dr.  Klotzsch 
(Keeper  of  the  Royal  Herbarium,  Berlin,  and  a  distin- 
guished botanist  and  vegetable  physiologist),  for  pre- 
venting the  ravages  of  the  potato  disease.  The  pro- 
posal of  Dr.  Klotzsch,  and  his  views  as  to  the  nature  of 
the  disease,  are  such  as  materially  to  strengthen  the 
opinions  expressed  on  this  subject  by  Baron  Liebig  (see 
pj>.  198,  seq.).  As  a  knowledge  of  the  method  suggested 
by  Dr.  Klotzsch  is  likely  to  be  interesting  to  many  of 
the  readers  of  this  work,  I  have  thought  it  right  to  give 
it  in  an  Appendix. 

WILLIAM  GREGORY. 


METHOD  PROPOSED  BY  DR.  KLOTZSCH  FOR  THE  PROTEC- 
TION OF  THE  POTATO  PLANT  AGAINST  DISEASES. 

"  The  potato,  which  is  an  annual  plant,  represents,  in 
the  tubers  developed  from  the  stem,  the  perennial  part 
of  a  plant.  For  while  the  duration  of  its  development 
is  analogous  to  that  of  annuals,  its  actions  coincide  ex- 
actly with  those  of  dicotyledonous  shrubs  and  trees. 

"  The  potato  plant  differs  from  all  those  plants  which 
are  cultivated  for  economical  purposes  in  Europe,  and 
can  only  be  compared  to  those  orchidious  plants  which 
yield  salep,  and  which  are  not  yet  cultivated  among  us. 


214  APPENDIX. 

"  The  tubers,  both  of  the  potato  and  of  the  salep 
plants,  are  nutricious,  and  agree  in  this,  that  in  the  cells 
of  the  tubers,  grains  of  starch,  with  more  or  less  azo- 
tized  mucilage,  are  collected,  while  the  cell  walls  pos- 
sess the  remarkable  property  of  swelling  up  into  a  jelly, 
and  thus  becoming  easily  digestible  when  boiled  with 
water. 

"  But  while  the  tuber  of  salep  contains  only  one  bud, 
or  germ,  the  potato  usually  develops  several,  even  many, 
germs. 

"  The  potato  plant,  like  all  annuals,  exerts  its  chief 
efforts  in  developing  flowers  and  fruit.  Like  all  annu- 
als, too,  it  has  the  power  of  shortening  this  period  of  de- 
velopment, when  the  power  of  the  roots  is  limited ;  as 
also  of  lengthening  it  when  the  extent  and  power  of  the 
roots  are  increased. 

"  We  observe  in  nature,  that  plants  with  feebly  de- 
veloped roots  often  have  a  weak,  sickly  aspect,  but  yet 
come  to  maturity  in  flower  and  fruit  sooner  than  strong- 
er individuals,  well  furnished  with  roots. 

"  In  perennial  plants,  we  observe  a  second  effort, 
which  is  directed  towards  preparing  and  storing  all  nu- 
tritious matter,  for  the  consumption  of  the  plant.  The 
preparation  of  this  nutriment  is  effected  by  the  physio- 
logical action  of  the  leaves,  under  the  influence  of  the 
roots.  The  stronger  and  larger  the  former  are,  the 
more  is  this  preparation  of  food  delayed. 

"  The  nutritious  matters  are  stored  in  the  colored 
stratum  of  the  bark  in  shrubs  and  trees,  and  in  the  tu- 
bers in  the  potato  and  salep  plants.  Not  only,  however, 
the  nutrient  matters,  but  also  the  cells,  owe  their  origin 
to  the  physiological  action  of  the  leaves. 

"  On  considering  these  things,  it  follows  that  the  pota- 
to plant  requires  more  care  than  is  usually  devoted  to  it. 
Hitherto  the  whole  cultivation  has  consisted  in  clearing 


APPENDIX.  215 

off  weeds,  and  hoeing  up  the  earth  round  the  stems. 
Both  of  these  measures  are  indeed  necessary,  but  they 
are  not  alone  sufficient ;  for  the  plant  is  cultivated,  not 
on  account  of  its  fruit,  but  for  the  sake  of  its  tubers, 
and  the  treatment  should  be  modified  accordingly. 

"  The  chief  points  to  be  attended  to,  with  a  view  to 
the  attainment  of  the  object,  namely,  the  increase  of  tu- 
bers, are,  — 

"1.  To  increase  the  power  in  the  roots  ;  and, 
"2.  To  check  the  transformation   which  occurs  in 
the  leaf. 

"  We  obtain  both  ends  simultaneously,  if,  in  the  5th, 
6th,  and  7th  week  after  setting  the  tubers,  and  in  the 
4th  and  5th  week  after  planting  out  germs  furnished 
with  roots,  or  at  a  time  when  the  plants  reach  the  height 
of  six  to  nine  inches  above  the  soil,  we  pinch  off  the 
extreme  points  of  the  branches  or  twigs  to  the  extent  of 
half  an  inch  downwards,*  and  repeat  this  on  every 
branch  or  twig  in  the  10th  and  llth  week,  no  matter  at 
what  time  of  day. 

"  The  consequence  of  this  check  to  the  develop- 
ment of  the  stem  and  branches  is  a  stimulus  to  the  nu- 
trient matters  in  the  plant  in  the  direction  of  the  in- 
crease both  of  roots  and  of  the  multiplication  of  the 
branches  of  the  stem  above  ground,  which  not  only  fa- 
vors the  power  of  the  root,  but  also  strengthens  the 
leaves  and  stalks  to  such  a  degree,  that  the  matters  pre- 
pared by  the  physiological  action  of  these  parts  are 
increased  and  applied  to  the  formation  of  tubers,  while 
at  the  same  time  the  direct  action  of  the  sun's  rays  on 
the  soil  is  prevented  by  the  thick  foliage,  and  thus  the 

*  Any  one  would  be  bitterly  disappointed,  who,  on  the  prin- 
ciple that  "  there  cannot  be  too  much  of  a  good  thing,"  should 
take  off  more  than  is  here  recommended,  in  order  to  use  it  as 
fodder 


216  APPENDIX. 

drying  up  of  the  soil  and  its  injurious  consequences  are 
avoided. 

"  The  checking  of  the  transformation  in  the  leaf  is 
equivalent  to  the  interruption  of  the  natural  change  of 
the  leaves  into  calyces,  corollse,  stamens,  and  pistils, 
which  is  effected  at  the  expense  of  the  nutrient  matters 
collected  in  the  plant ;  and  these,  when  this  modifica- 
tion of  the  leaves  is  arrested,  are  turned  to  account  in 
the  formation  of  tubers. 

"  Led  by  these  views,  I  made,  in  1846,  experiments 
on  single  potato  plants,  carefully  marked,  by  pinching 
off  the  ends  of  the  branches.  They  were  so  readily 
distinguished  in  their  subsequent  growth  from  the  plants 
beside  them,  by  more  numerous  branches,  larger  and 
darker  foliage,  that  in  truth  no  marking  was  necessary. 

"  The  produce  from  these  plants  of  tubers  was  abun- 
dant, and  the  tubers  were  perfectly  healthy ;  while  the 
plants  next  them  which  had  not  been  so  treated,  gave 
uniformly  a  less  produce,  at  the  same  time  the  tubers 
were  rough  on  the  surface,  and  in  many  instances  at- 
tacked with  the  prevailing  disease.  This  experiment 
was  incomplete,  and  did  not  give  a  positive  result,  but 
it  was  yet  encouraging  for  me. 

"  In  the  middle  of  April,  1847,  an  experiment  was 
made  on  a  low-lying  field  with  the  round  white  pota- 
toes generally  cultivated  here,  a  variety  which  had 
not  suffered  much  from  the  disease  which  first  appeared 
here  in  1845.  The  potatoes  were  planted  in  the  usual 
way,  by  an  experienced  farm  servant. 

"  After  weeding  them  in  the  end  of  May,  I  renewed 
my  experiment  by  pinching  off  the  points  of  the  branch- 
es of  every  second  row,  and  repeated  this  in  the  end  of 
June.  The  result  surpassed  all  expectations.  The 
stalks  of  the  plants  not  treated  on  my  plan  were  long, 
straggling,  and  sparingly  furnished  with  leaves,  the 
leaves  themselves  small  and  pale  green. 


APPENDIX.  217 

"  In  the  next  field,  potatoes  of  the  same  variety  were 
planted  on  the  same  day,  and  left  to  nature.  They  ap- 
peared in  the  first  six  weeks  healthy,  even  strong,  but 
gradually  acquired  a  poor  aspect  as  the  time  of  flower- 
ing and  fruit  approached,  and  finally  exhibited  precisely 
the  same  appearances  as  the  rows  not  treated  by  pinch- 
ing off  the  extremities  in  the  field  in  which  my  experi- 
ments were  made. 

"  The  harvest  began  in  the  surrounding  fields  in  the 
middle  of  August,  and  was  very  middling.  The  tubers 
were  throughout  smaller  than  usual,  very  scabby,  and, 
within  these  fields,  to  a  small  extent,  attacked  by  the 
wet  rot. 

"  In  the  end  of  August,  the  difference  between  the 
rows  treated  by  me  and  those  not  treated  became  so 
striking,  that  it  astonished  all  the  work-people  in  the 
neighbourhood,  who  were  never  tired  of  inquiring  the 
cause.  The  stalks  of  the  rows  left  to  themselves  were 
all  now  partly  dried,  partly  dead.  On  the  contrary,  the 
rows  treated  as  above  were  luxuriant  and  in  full  vigor, 
the  plants  bushy,  the  foliage  thick,  the  leaves  large  and 
dark  green,  so  that  most  people  supposed  they  had  been 
later  planted. 

"  But  the  difference  in  the  tubers  was  also  very  de- 
cided. The  tubers  of  the  plants  in  the  rows  treated  on 
my  plan  were  not  indeed  larger,  but  vastly  more  nu- 
merous, and  they  were  neither  scabby  nor  affected  with 
any  disease  whatever.  A  few  had  pushed  (which  was 
to  be  ascribed  to  a  late  rain),  and  were  apparently  in- 
completely developed,  while  scab  and  wet  rot  attacked 
more  and  more  the  tubers  of  the  other  plants,  which 
also  fell  off  on  the  slightest  handling. 

"  Although  I  am  far  from  believing  that  I  am  able  to 
explain  the  nature  of  the  potato  disease  which  has  visited 
us  of  late  years,  yet  I  feel  certain  that  I  have  discov- 
19 


218  APPENDIX. 

ered  a  means  of  strengthening  the  potato  plant  to  such 
a  degree  as  to  enable  it  to  resist  the  influences  which 
determine  such  diseases. 

"  Should  any  one  be  deterred  from  continuing  the 
cultivation  of  potatoes  on  account  of  the  manipulation 
here  recommended,  which  may  be  performed  by  women 
and  even  by  children,  I  would  remind  him  that  the  same 
field  planted  with  potatoes  is  capable  of  supplying  food 
to  twice  as  many  persons  as  when  employed  to  grow 
wheat."  —  (From  the  Annals  of  Agriculture  in  Prus- 
sia, edited  by  the  College  of  Rural  Economy.) 


Dr.  Klotzsch  presented  to  the  king  of  Prussia  a  me- 
morial, offering  to  give  to  the  world  his  method  of  pre- 
venting disease  in  potatoes,  provided  he  were  assured  of 
a  remuneration  of  2,000  dollars  (about  $  1,400),  if,  after 
three  years'  experience,  it  should  be  found  efficacious. 

The  king  handed  the  memorial  to  the  Minister  of  the 
Interior,  who  requested  the  College  of  Rural  Economy 
to  discuss  the  matter  with  Dr.  Klotzsch. 

The  president  of  the  College  undertook  the  arrange- 
ment, and,  after  Dr.  Klotzsch  had  explained  to  him  pri- 
vately his  method,  reported  most  favorably  of  it  to  the 
College,  which  unanimously  recommended  that  the  very 
moderate  remuneration  asked  for  by  Dr.  Klotzsch  should 
be  secured  to  him  on  the  following  conditions,  which 
were  accepted  by  him. 

1.  That  the  College  of  Rural  Economy  should  be 
the  judges  of  the  efficacy  of  the  proposed  method. 

2.  That  their  decision  should  be  given,  at  latest,  with- 
in  three    years,  provided  the   potato   disease,  against 
which  the  plants  are   to  be   protected,  should  appear 
during  that  period. 

The  Minister  of  the  Interior  approved  of  the  recom- 


APPENDIX.  219 

mendation,  and  authorized  the  College  to  conclude  an 
agreement  with  Dr.  Klotzsch. 

The  agreement  has  been  concluded,  and  now  the 
method  is  published,  that  it  may  be  tried  and  tested  as 
widely  as  possible  by  comparative  experiments,  similar 
to  those  made  by  Dr.  Klotzsch  himself.  The  cost  of  it 
is  stated  not  to  exceed  35  cents  per  acre  in  Germany. 

It  is  very  desirable  that  this  method  should  be  tried 
in  the  British  islands,  and  as  the  season  for  trying  it 
now  approaches,  I  have  here  given  Dr.  Klotzsch's  ac- 
count entire. 

WILLIAM  GREGORY. 


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